white dwarf stars as probes of galaxy evolution and

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4Physics Department, Sharif University of Tecnology, Tehran 1458889694, Iran. 5Instituto de ...... Yaseen Almleaky *1 and Michaël Gillon†. *King Abdul Aziz ...
WHITE DWARF STARS AS PROBES OF GALAXY EVOLUTION AND FUNDAMENTAL PHYSICS Maurizio Salaris1 Astrophysics Research Institute, Liverpool John Moores University, 146 Brownlow Hill, Liverpool L3 5RF, United Kingdom White dwarfs (WDs) are the final evolutionary phase of the large majority of stars populating the universe, including our own Sun. With no active nuclear reactions, WD evolution is a cooling process, whereby the star slowly cools down and gets dimmer with time. Despite their deceptively simple structure (a carbon/oxygen core supported by electron degeneracy pressure, that makes 99% of the star mass, plus thin non degenerate H and He envelopes) a detailed description of the structure and evolution of the cold and dense WD cores requires modelling complex processes like phase transitions, crystallization, diffusion of the ionic component. This modelling, in turn, requires an accurate knowledge of the inner chemical stratification, built up during the previous evolutionary phases. The existence of a well defined relationship between WD luminosity and cooling times, as well as the long cooling timescales, make WDs very attractive candidates to unveil the history of star formation in our galaxy. In addition, theoretical estimates of white dwarf cooling rates are routinely adopted to place constraints on the properties of neutrinos, dark matter candidates and alternative theories of gravity. This talk will discuss the basics of WD evolution, latest and future developments of WD research in age dating of Galactic populations, tests of WD structure, and constraints on exotic physics posed by WD observations.

1

Email: [email protected]

STELLAR POPULATION MODELS FOR ANALYZING STAR CLUSTER SPECTRA Alexandre Vazdekis *1 *

Instituto de Astrof´ısica de Canarias (IAC), E-38200 La Laguna, Tenerife, Spain

Stellar population synthesis models are required to interpret the integrated light of star clusters with varying ages and metallicities. I will present our latest model developments, which include an extension of the spectral range coverage and varying abundance element ratios. The models, which are publically available, were properly calibrated with old and young star cluster data, showing us their strengths and limitations. The obtained results as well as the various approaches to derive relevant stellar population properties for these clusters, both young and old, are also discussed. References 1. http://miles.iac.es

1

Email : [email protected]

GAMMA-RAY BURSTS: CHARACTERISTICS AND PROSPECTS Walid J. Azzam*1, Hannachi Zitouni†, Nidhal Guessoum** *

Department of Physics, College of science, University of Bahrain, Kingdom of Bahrain † PTEAM Laboratory, Faculty of Science, University Dr. Yahia Fares, Algeria ** Department of Physics, American University of Sharjah, UAE

Gamma-ray bursts (GRBs) are the most powerful explosions in the universe. They have remained the object of intense research ever since their discovery was declassified in the early 1970s. Several space-borne missions have been dedicated to their study including the Compton Gamma-Ray Burst Observatory (CGRO) in the 1990s and the current Swift and Fermi satellites. However, despite several decades of focused research, the precise mechanism behind these enigmatic explosions has remained elusive. In the first part of this paper, we review what is currently known about GRBs. This includes GRB light-curves and spectra; the different progenitor models like the "collapsor" and merger models; the various classification schemes; the afterglow characteristics including external shocks and the surrounding medium; host galaxies; and the possible association of some gravitational waves with GRBs [1, 2]. In the second part of the paper, we present our work which focuses on utilizing GRBs as cosmological probes. GRBs are ideal cosmological tools because they have been observed to great distances (redshifts up to z = 9.4) and their radiation is unencumbered by any intervening dust. Although GRBs are not standard candles, the discovery of several energy and luminosity correlations, like the Amati relation [35] which correlates the intrinsic spectral peak energy, Ep,i, to the equivalent isotropic energy, Eiso, has ushered in a new era in which GRBs are used to investigate cosmological issues like the star formation rate and the value of the matter-density parameter, M. In this paper, we present the results of a recent study that we have conducted in which we recalibrate the Amati relation and then use it to put limits on the value of M.

References 1. 2. 3. 4. 5.

1

G. Vedrenne and J.-L. Atteia, Springer: Berlin (2009). C. Kouveliotou et al., Cambridge U. Press: Cambridge (2012). L. Amati et al., Astron. & Astroph. 390, 81 (2002). L. Amati et al., Astron. & Astroph. 508, 173 (2009). H. Zitouni, N. Guessoum, and W. J. Azzam, Astroph. & Space Sci. 351, 267 (2014).

Email : [email protected]

STAR CLUSTERS AS PROBES OF GALAXY FORMATION Michael A. Beasley∗1 Instituto de Astrof´ısica de Canarias (IAC), E-38205 La Laguna, Tenerife, Spain Universidad de La Laguna, Dpto. Astrof´ısica , E-38206 La Laguna, Tenerife, Spain Star clusters are fundamental tools for investigating a wide range of problems in astrophysics. Examples include their utility in the development and calibration of the latest generation of stellar population models, their use as tracers of the star formation and temporal evolution of the discs of spiral galaxies, and their uniquely powerful role as dynamical probes of the dark mass distributions of dwarf and giant galaxies. In this contribution I will discuss recent work on each of these areas, paying special attention to the pivotal role star clusters are playing in unravelling the properties of ultra-faint stellar systems.

Figure 1. g, V, I HST/ACS composite image of globular clusters (circled) around the ultra-diffuse galaxy DF17 in the Coma cluster. Based on the size of the globular cluster population, this galaxy has an inferred dark-to-stellar mass ratio of ∼ 1000 [1]

References 1. M.A. Beasley and I. Trujillo, ApJ in press, (2016) 1

Email: [email protected]

MULTIPLE STELLAR POPULATIONS IN GALACTIC GLOBULAR CLUSTERS Santi Cassisi*1 *

INAF – Astronomical Observatory of Teramo, Via M Maggini, sn, 64100 Teramo, Italy

The discovery of distinct sub-populations in Galactic globular clusters is one of the most important and intriguing achievements of stellar astrophysics research. We discuss the most important observational evidence of the multiple stellar population phenomenon from both a photometric and spectroscopic point of view. We also review the most important empirical results in this context as obtained from recent photometric surveys. The theoretical framework required in order to fully interpret the various observational results, and the physical scenarios that have been envisaged in order to explain the presence of these subpopulations in individual clusters are also discussed in some detail.

1

Email : [email protected]

NOT-SO-SIMPLE STELLAR POPULATIONS IN NEARBY, RESOLVED MASSIVE STAR CLUSTERS Richard de Grijs* *

Kavli Institute for Astronomy and Astrophysics, Peking University, China

Until about a decade ago, star clusters were considered "simple" stellar populations: all stars in a cluster were thought to have similar ages and the same metallicity. Only the individual stellar masses were thought to vary, in essence conforming to a "universal" initial mass function. Over the past decade, this situation has changed dramatically. Yet, at the same time, star clusters are among the brightest stellar population components and, as such, they are visible out to much greater distances than individual stars, even the brightest, so that understanding the intricacies of star cluster composition and their evolution is imperative for understanding stellar populations and the evolution of galaxies as a whole. I will discuss my group's recent progress in this context, with particular emphasis on the properties and importance of binary systems, the effects of rapid stellar rotation, and the presence of multiple populations in Local Group star clusters across the full age range. Our most recent results imply a reverse paradigm shift, back to the old simple stellar population picture for at least some intermediate-age (~2 Gyr-old) star clusters, which opens up exciting avenues for future research efforts.

IMPROVING MASS AND AGE ESTIMATES OF STELLAR CLUSTERS, NEAR AND FAR Margaret Hanson*1, Bogdan Popescu*, Randa Asa’d† *



Department of Physics, University of Cincinnati, Ohio, U.S.A. Physics Department, American University of Sharjah, Sharjah, U.A.E.

Stellar clusters equip astronomers with powerful benchmarks to derive the history and evolution of the galaxies they reside in, provided accurate values of cluster mass, age and distribution can be obtained. However, traditional methods suffer severe challenges in locating and then deriving mass and age estimates of stellar clusters within our own Milky Way galaxy, as well as more distant, unresolved clusters in galaxies beyond our Local Group. We have spent several years developing a robust suite of programs that combine the power of Monte Carlo methods with sophisticated statistical inference. This program is called MASSCLEAN.

Figure 1. The steps in creating simulated stellar cluster images and integrated photometric bands with the software package, MASSCLEAN [1]. I will describe how this novel analysis successfully overcomes many of the historical challenges found in traditional methods for locating and deriving characteristics of stellar clusters, near and far. References

1. B. Popescu and M. M. Hanson, AJ 138, 1724 (2009)

1

Email : [email protected]

WHITE DWARF STARS AS PROBES OF GALAXY EVOLUTION AND FUNDAMENTAL PHYSICS Maurizio Salaris1 Astrophysics Research Institute, Liverpool John Moores University, 146 Brownlow Hill, Liverpool L3 5RF, United Kingdom White dwarfs (WDs) are the final evolutionary phase of the large majority of stars populating the universe, including our own Sun. With no active nuclear reactions, WD evolution is a cooling process, whereby the star slowly cools down and gets dimmer with time. Despite their deceptively simple structure (a carbon/oxygen core supported by electron degeneracy pressure, that makes 99% of the star mass, plus thin non degenerate H and He envelopes) a detailed description of the structure and evolution of the cold and dense WD cores requires modelling complex processes like phase transitions, crystallization, diffusion of the ionic component. This modelling, in turn, requires an accurate knowledge of the inner chemical stratification, built up during the previous evolutionary phases. The existence of a well defined relationship between WD luminosity and cooling times, as well as the long cooling timescales, make WDs very attractive candidates to unveil the history of star formation in our galaxy. In addition, theoretical estimates of white dwarf cooling rates are routinely adopted to place constraints on the properties of neutrinos, dark matter candidates and alternative theories of gravity. This talk will discuss the basics of WD evolution, latest and future developments of WD research in age dating of Galactic populations, tests of WD structure, and constraints on exotic physics posed by WD observations.

1

Email: [email protected]

DISCOVERY OF A NEW STELLAR POPULATION IN THE HEART OF THE GALAXY BY APOGEE Ricardo Schiavon*1 and the APOGEE team *

Astrophysics Research Institute, Liverpool John Moores University

I will report the discovery of a new population of field stars in the inner Galaxy. Located within a few kiloparsecs of the Galactic centre, these stars have chemical compositions that are typical of globular cluster stars. The newly discovered stars are homogeneously distributed across, and kinematically indistinguishable from the dominant stellar populations in the inner Galaxy. The metallicity distribution of this new stellar population appears to be unimodal, peaking at [Fe/H] ∼ −1, thus being in disagreement with both that of the inner Galaxy and that of the Galactic globular cluster system. Under the hypothesis that these stars have once been gravitationally tied to globular clusters, our results have the following implications: 1) these early globular clusters were completely destroyed; 2) the total mass contained in these destroyed globular clusters exceeded that of the existing Galactic globular cluster system by a factor of several. The discovery was made possible by the Apache Point Observatory Galactic Evolution Experiment (APOGEE), which is part of the third version of the Sloan Digital Sky Survey (SDSS-III). Besides providing a brief description of the APOGEE (Apache Point Observatory Galactic Evolution Experiment) survey and data, I will briefly discuss the possible scenarios that may explain the origin of these stars.

1

Email : presenting [email protected]

STELLAR POPULATION MODELS FOR ANALYZING STAR CLUSTER SPECTRA Alexandre Vazdekis *1 *

Instituto de Astrof´ısica de Canarias (IAC), E-38200 La Laguna, Tenerife, Spain

Stellar population synthesis models are required to interpret the integrated light of star clusters with varying ages and metallicities. I will present our latest model developments, which include an extension of the spectral range coverage and varying abundance element ratios. The models, which are publically available, were properly calibrated with old and young star cluster data, showing us their strengths and limitations. The obtained results as well as the various approaches to derive relevant stellar population properties for these clusters, both young and old, are also discussed. References 1. http://miles.iac.es

1

Email : [email protected]

MULTIPLE STELLAR POPULATIONS IN GALACTIC GLOBULAR CLUSTERS Santi Cassisi*1 *

INAF – Astronomical Observatory of Teramo, Via M Maggini, sn, 64100 Teramo, Italy

The discovery of distinct sub-populations in Galactic globular clusters is one of the most important and intriguing achievements of stellar astrophysics research. We discuss the most important observational evidence of the multiple stellar population phenomenon from both a photometric and spectroscopic point of view. We also review the most important empirical results in this context as obtained from recent photometric surveys. The theoretical framework required in order to fully interpret the various observational results, and the physical scenarios that have been envisaged in order to explain the presence of these subpopulations in individual clusters are also discussed in some detail.

1

Email : [email protected]

NOT-SO-SIMPLE STELLAR POPULATIONS IN NEARBY, RESOLVED MASSIVE STAR CLUSTERS Richard de Grijs* *

Kavli Institute for Astronomy and Astrophysics, Peking University, China

Until about a decade ago, star clusters were considered "simple" stellar populations: all stars in a cluster were thought to have similar ages and the same metallicity. Only the individual stellar masses were thought to vary, in essence conforming to a "universal" initial mass function. Over the past decade, this situation has changed dramatically. Yet, at the same time, star clusters are among the brightest stellar population components and, as such, they are visible out to much greater distances than individual stars, even the brightest, so that understanding the intricacies of star cluster composition and their evolution is imperative for understanding stellar populations and the evolution of galaxies as a whole. I will discuss my group's recent progress in this context, with particular emphasis on the properties and importance of binary systems, the effects of rapid stellar rotation, and the presence of multiple populations in Local Group star clusters across the full age range. Our most recent results imply a reverse paradigm shift, back to the old simple stellar population picture for at least some intermediate-age (~2 Gyr-old) star clusters, which opens up exciting avenues for future research efforts.

NUCLEOSYNTHESIS IN RELATION TO COSMOLOGY Mounib F. El Eid*1 *

American University of Beirut, Department of physics, Beirut, Lebanon

While the primordial (or Big Bang) nucleosynthesis delivers important clues about the conditions in the high red shift universe (far-field cosmology), the nucleosynthesis of the heavy elements beyond iron by the r-process or the s-process bears information about the early phase and history of the galaxy(near-field cosmology). In particular the r-process nucleosynthesis is unique, because it is a primary process that helps to tag or to associate individual stars with the composition of the protocloud. The present talk is intended to give an overview about these nucleosynthesis processes and their link to stellar evolution and to the chemical evolution of the galaxy.

1

Email : [email protected]

A REVIEW OF FR II RADIO SOURCES PROPERTIES Ilias M. Fernini *1 *

Department of Applied Physics and Astronomy, University of Sharjah, Sharjah, P.O. Box: 27272, UAE

I will review the radio properties of the Fanaroff-Riley type II (FR II) radio sources in light of the 1989 unification scheme of Barthel. The idea behind this scheme is to unify radio loud FRII quasars (QSRs) and FRII radio galaxies (RGs) as members of the same parent active galactic nuclei (AGN) population but observed through different orientations to the line of sight. In particular, I will report on the VLA observations of 52 RGs and 46 quasars QSRs at several wavelengths, i.e., 3.6, 6, and 20 cm. The two samples were compared in terms of the jet/counterjet detection rate, the radio core detection, the depolarization asymmetry, and the hot spots (HSs) morphologies and occurrence. The jet detection rate was found to be 85% for the QSRs (with six counterjet candidates), and 23% for the RGS (with no counterjet candidate). This jet detection rate is consistent with the prediction of the unification scheme. For the core detection rate, it is 100% and 92% for the QSRs and the RGs, respectively. For the 6 and 20 cm observations, the two samples were used to check the LaingGarrington effect in which the radio lobe of an FR II on the jet side is invariably less depolarized than the counterjet lobe. Our results show no clear difference in the distribution of the depolarization asymmetry ratios between the RGs and QSRs. At 3.6 cm, the RGs and QSRs were compared in terms of the compactness and location (i.e., edged or recessed) of their HSs being on the jet or counterjet side. In terms of HSs occurrence, the jetted sources (QSRs) have more recessed hot spots than the unjetted sources (RGs). The tendency is for the QSRs to have more compact HSs than the RGs. Our results will be analyzed in terms of their implications for models of radio sources.

1

Email : [email protected]

IMPROVING MASS AND AGE ESTIMATES OF STELLAR CLUSTERS, NEAR AND FAR Margaret Hanson*1, Bogdan Popescu*, Randa Asa’d† *



Department of Physics, University of Cincinnati, Ohio, U.S.A. Physics Department, American University of Sharjah, Sharjah, U.A.E.

Stellar clusters equip astronomers with powerful benchmarks to derive the history and evolution of the galaxies they reside in, provided accurate values of cluster mass, age and distribution can be obtained. However, traditional methods suffer severe challenges in locating and then deriving mass and age estimates of stellar clusters within our own Milky Way galaxy, as well as more distant, unresolved clusters in galaxies beyond our Local Group. We have spent several years developing a robust suite of programs that combine the power of Monte Carlo methods with sophisticated statistical inference. This program is called MASSCLEAN.

Figure 1. The steps in creating simulated stellar cluster images and integrated photometric bands with the software package, MASSCLEAN [1]. I will describe how this novel analysis successfully overcomes many of the historical challenges found in traditional methods for locating and deriving characteristics of stellar clusters, near and far. References

1. B. Popescu and M. M. Hanson, AJ 138, 1724 (2009)

1

Email : [email protected]

THE STATUS OF DARK MATTER DIRECT SEARCHES Francesco Arneodo* *New York University Abu Dhabi, (Abu Dhabi, UAE) The scenario of Dark Matter direct searches continues to be extremely lively and diversified. Old players have developed their techniques to full maturity, taking the sensitivity to WIMPs to unprecedented levels, while more recent technologies are starting to become competitive. I will illustrate the status of the more advanced experiments and programs, with a special emphasis on the recent developments of noble liquid Time Projection Chambers.

INTERMEDIATE FLARES FROM MAGNETARS Alaa Ibrahim*,†1 *

Zewail City of Science and Technology Cairo, Egypt † American University in Cairo, Cairo, Egypt

Magnetars are neutron stars that possess the highest observed magnetic field in the universe (B ~ 101516 G). Unlike other astrophysical compact objects, the ultra-strong magnetic field provides the dominant source of free energy that powers the electromagnetic and particle radiation of this class of neutron stars. The observed activities of magnetars include persistent x-ray emission (at luminosities higher than what rotational energy losses can offer), short recurrent bursts of soft gamma-ray, and giant flares of hard gamma-ray that typically exceed the Edington luminosity. A sub-class of bursts known as intermediate flares is characterized by a temporal profile that is longer and more energetic than short bursts, but still shorter and less luminous than giant flares. While the short bursts and the giant flares have been well studied, intermediate flares pose unanswered questions on the possible continuum of burst emission and the connection to short and giant flare bursts. We present a study of magnetar intermediate flares that (a) constrains the physical processes that govern the emission, (b) characterizes their spectral and temporal properties, and (c) utilizes the results to infer the neutron star fundamental properties and probe the interaction of radiation and matter in the unique magnetar environment of extreme gravity, temperature, density, and magnetic field.

1

Email : [email protected]

DISCOVERY OF A NEW STELLAR POPULATION IN THE HEART OF THE GALAXY BY APOGEE Ricardo Schiavon*1 and the APOGEE team *

Astrophysics Research Institute, Liverpool John Moores University

I will report the discovery of a new population of field stars in the inner Galaxy. Located within a few kiloparsecs of the Galactic centre, these stars have chemical compositions that are typical of globular cluster stars. The newly discovered stars are homogeneously distributed across, and kinematically indistinguishable from the dominant stellar populations in the inner Galaxy. The metallicity distribution of this new stellar population appears to be unimodal, peaking at [Fe/H] ∼ −1, thus being in disagreement with both that of the inner Galaxy and that of the Galactic globular cluster system. Under the hypothesis that these stars have once been gravitationally tied to globular clusters, our results have the following implications: 1) these early globular clusters were completely destroyed; 2) the total mass contained in these destroyed globular clusters exceeded that of the existing Galactic globular cluster system by a factor of several. The discovery was made possible by the Apache Point Observatory Galactic Evolution Experiment (APOGEE), which is part of the third version of the Sloan Digital Sky Survey (SDSS-III). Besides providing a brief description of the APOGEE (Apache Point Observatory Galactic Evolution Experiment) survey and data, I will briefly discuss the possible scenarios that may explain the origin of these stars.

1

Email : presenting [email protected]

SMALL BODIES AND EXOPLANETES FROM OUKAIMEDEN OBSEVATORY Zouhair Benkhaldoun*1 *

High Energy Physics and Astrophysics Laboratory, Oukaimeden Observatory, Cadi Ayyad University, FSSM, Av Prince My Abdallah, BP2390, Morocco

Oukaimeden Observatory from Cadi Ayyad University in Morocco (OUCA) has become one of the best active NEO search facilities in the word. Its discovery statistics shows that the MOSS (Morocco Oukaimeden Sky Survey)[1] project received credits for more than 3,000 new designations, including 4 NEOs and 4 comets. The site has been recently (June 2016) equipped with a new performed telescope (see Fig. 1). TRAPPIST-North, the twin of the telescope that was installed in 2010 at the observatory of La Silla in Chile and that recently made the important discovery of the closest planetary system to Earth containing potentially habitable terrestrial planets [3]. The aims goals of this new telescope, is related to the detection and study of exoplanets, and the study of comets and other small bodies in the solar system to better understand the genesis of the solar system and our Earth in particular.

Figure 1. TNR First Light with in the right bottom, the telescope at Oukaimeden Observatory [2]. The success of the observatory is partly due to its excellent astro-climactic characteristics. In fact, the average number of observable nights is around 280 nights per year, while median seeing is 0.8-0.9 arcsec [4]. We present here a brief description of MOSS and TNR instruments. We also set out some of the most important latest observations along with their critical analysis. References http://moss-observatory.org/ 2. Galaxy M51, Copyright: Emmanuel Jehin and TRAPPIST Team 3. J. de Wit et al., Nature 537, Issue 7618, 69-72 (2016) 4. Z. Benkhaldoun Z.et al., A& A 441, Issue 2, 839-843 (2005) 1

Email : [email protected]

Local OB Associations, Supernovae and the Environment of the Solar System Athem Alsabti, University College London, [email protected] Stellar associations such as Scorpius-Centaurus and Orion OB1 are the cradle where massive young stars are born and also undergo explosion and mostly as core-collapse supernovae in the neighbourhood of the solar system. Consequences of activities of these clusters are investigated in connection with the environment of the solar system. These influence include the effects of direct supernova explosion on the solar system, the remnants of expanding supernova shell as a source of galactic cosmic rays, effects of features created by multiple supernova explosion and cavities of hot less dense gas created such as the Local Bubble. Other effects include the creation of pulsars, ejection of stars, runaway stars in binary systems as well as dust and neutrals created by circumstellar and in the interstellar medium. We also investigate the possible effects on earth and planets within the heiosphere such as space weather, planetary climates as well as isotopic influence deposited on the surface. We conclude by presenting evidence for nearby supernova explosion in recent history.

SEARCH FOR BEST ASTRONOMICAL OBSERVATORY SITES IN THE ARAB WORLD USING SATELLITE MEASUREMENTS Gillali Abdelaziz1, Ridha Guebsi1,2, Nidhal Guessoum3,*, Cyrille Flamant1 1

Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS)/IPSL, Université Pierre et Marie Curie Paris 06, Sorbonne Universités, CNRS, Paris, France 2 National Mapping and Remote Sensing Center, Tunisia 3 American University of Sharjah, UAE

The Arab world currently has only one optical astronomy telescope larger than 1 meter in diameter (the Kottamia Observatory in Egypt built more than 50 years ago), and this has led to calls [1] for urgent construction of international-class observatories in the region, which is blessed with hundreds of clear nights per year. And despite the existence of a decent-sized astronomical community (professionals and amateurs) in the Arab world, few observatories have been built in recent years, and they host telescopes of only 50-60 cm size. Guessoum and co-workers recently performed a preliminary search for the best astronomical observatory sites in the Middle East and North Africa [2]. Starting with locations of altitudes higher than 1,500 m, meteorological and other data (number of clear nights per year, humidity, temperature profile, wind speed, light pollution from nearby towns) were collected using online databases and published data. Considering the shortcomings of that work (inability to do in-situ measurements, necessary interpolations and approximations due to the lack of data on some factors at the sites of interest, etc.), and realizing that this problem can be addressed through the rich data that Earth-observing satellites can provide, e.g. the Terra and Aqua multi-national research satellites, with their MODIS (Moderate-resolution Imaging Spectroradiometer) and AIRS (Atmospheric Infrared Sounder) instruments, we have undertaken a thorough and systematic search of astronomical observatory sites using real space-based data for all factors. We have decided to look for the best locations for all Arab countries, even those that may not have any altitude higher than 1,500 m (the threshold in the previous study) or where the combination of factors (altitude, meteorological conditions, light pollution) had previously ended up excluding all locations in that given country. We here present preliminary results on the best location(s) for each country as well as a general ranking of all the best locations in the region. References: 1. Guessoum, N., Time for an Arab astronomy renaissance, Nature, 498, 161–164 (13 June 2013). 2. Guessoum, N., Alsaeed, N., Abdelhafez, N., Preliminary search for astronomical observatory sites in the MENA region, The Observatory, 134, 339-34 (Dec. 2014). *

Email: [email protected]

THE CROSS-CALIBRATION BETWEEN DIMM AND ISM MONITORS Abdelbasset Rabbah 1 , Abdefetah Habib 1,2 , Sabil mohammed 1 , Benkhaldoun Zouhair 1,3 , Youssef El Azhari 1 1

LPHEA, Cadi Ayyad University, Av. Prince My Abdellah, BP 2390 Marrakech, Morocco. 2 CRMEF-Marrakech, Av. Mouzdalifa, BP 797 Marrakech, Morocco. 3 Oukaimeden Observatory, Cadi Ayyad University, BP 2390 Marrakech, Morocco.

Optical turbulence is a very important factor in the astronomy observation, it limits Considerably the resolution of our telescopes. So to solve this problem It is necessary to understand the atmospheric turbulence its origins, parameters Which characterize it ... etc. The principal purpose of the turbulence characterization is the correction of the Deformed wave fronts arriving from the stars by a system of adaptable mirrors (adaptive optics). For this purpose a lot of interferometric techniques are used (ISM, SSS, Mass, DIMM, SCIDAR ...).

Figure 1. result of the night 22/01/20016.

ISM [1] and DIMM [2] are tow techniques measure the seeing value seeing = 0, 976 rλ0 [3] where λ is the visible wavelength (λ ≈ 0.5µm) and r0 Fried’s parameter. Our technique based on the study of the diffraction pattern produced by a double slit at the focus plane of a telescope. In the cross-calibration work we use tow telescopes separated per one mitre maximum. One with ISM masque and the other with the DIMM, after we focus on a star at the zenith (few perturbation) we start the measure. We make a lot of observations missions at differences sites. At Oukaimeden Observatory and Atlas cultural centre at Marrackech. And we have a good results as shown above. Our object is : - Compare the technique of ISM invented by Mr Habib and al with the DIMM which remains the standard technique for measuring seeing, which is called the cross-calibration of the two methods. - Validate and improve the ISM model at the level of the program used in the calculations. - Constructs a mask with adjustable slits to see the effect of the dimension of the slits on the measurement (objective realized in a master subject) References 1. A.Habib et all, Numerical simulations of a new approach for seeing measurement,2013 2. Sarazin & Roddier 1990 3. Hufnagel and Stanley,Modulation Transfer Function Associated with Image Transmission through Turbulent Media, 1964

BEHAVIOR ON THE POST-MAXIMUM HELIUM EMISSION IN THE D3 LINE IN RR LYRAE STAR A. Benhida1, F.L. Sefyani1, Z. Benkhaldoun2, T. De France3, D. Gillet4, P. Mathias5,6, M. Lazrek2, D. El Youssoufi2, A. Daassou2 1

Oukaïmeden Observatory. LPHEA. FSTG. Cadi Ayyad University. BP 618 Marrakech. Morocco. e-mail: [email protected], [email protected], 2 Oukaïmeden Observatory. LPHEA. FSSM. Cadi Ayyad University, BP 2390 Marrakech. Morocco., 3 AAVSO (American Association of Variable Star Observers), 49 Bay State Rd, Cambridge, MA 02138, USA 4 Observatoire de Haute-Provence - CNRS/PYTHEAS/Université d’Aix-Marseille, 04870 Saint Michel l’Observatoire, France 5 Université de Toulouse, UPS-OMP, Institut de Recherche en Astrophysique et Planétologie, Toulouse, France 6 CNRS, UMR5277, Institut de Recherche en Astrophysique et Planétologie, 14 Avenue Edouard Belin, 31400 Toulouse, France ABSTRACT

A helium emission in RR Lyrae stars was unexpectedly found by Preston [1] in a sampling of 11 observed RRab stars, among which eight are Blazhko stars. The strongest He I emission (D3 line at λ5875.66 and the weaker emission at λ6678.16) were detected in all observed stars during rising light. In addition, a very weak He II emission at λ4685.68 was also detected at the same phase by Preston [2], but only in three Blazhko stars. Helium emissions are expected to be formed in the de-excitation region of the shock wake. For the first time, Preston [1] also observed a post-maximum helium emission in the D3 line in one RRab Blazhko star : RV Oct. The intensity of this emission is weak. The physical explanation of the reappearance of helium emission near maximum light is not known yet. As reported by Preston [2] and Gillet et al. [3], they also observed the reappearance of a weak D3 emission after maximum light. Recently, we observed the D3 post-maximum helium emission in RR Lyrae for the first time [4]. We suggest that this profile is a natural consequence of the large extension of the expanding atmosphere induced by the main strong shock occurring at each pulsation cycle. We conducted an observation program of this RR Lyrae star over two months covering all phases Blazhko. Highresolution spectra of RR Lyrae, are collected with a spectrograph eShel/C14 at the Oukaïmeden Observatory (J43) during summer 2015. We will present the evolution of the intensity and the line broadening of this post-maximum helium emission in the D3 line in RR-Lyrae depending on the pulsation and/or Blazhko phase. References : 1. 2. 3. 4.

G. W. Preston, A&A. 507, 1621 (2009) G. W. Preston, ApJ. 6, 141 (2011) D. Gillet, N. Fabas and A. Lèbre, A&A, A59, 553 (2013) D. Gillet, F.L. Sefyani, A. Benhida, N. Fabas, P. Mathias, Z. Benkhaldoun and A. Daassou, A&A. A134, 587 (2016)

Sun and Sunspot Temperature Measurement Using Image Processing Technique by Matlab A. Hatami1, B. Mahdavipour, A. Salar Elahi Plasma physics Research Center, Science and Research Branch, Islamic Azad University, Tehran, Iran

Abstract Image processing technique (IPT) is a computation technique which is a cheap, wide and great technique. In this paper, we used the IPT to obtain the sun and sunspot temperature. The sun image was taken by the telescope and DSLR camera and imported to the MATLAB software. By using the IPT we cropped two parts on the sun as sun surface and sunspot, and then we evaluate their RGB value.By using our code which was written according to Tabble1,2 by Python Software, we computed our sample wavelength. Substituting the wavelength in Wien’s law gave us the sun surface and sunspot temperature at last which were in their range of temperature [1]. The temperature error for sun surface and sunspot was 0.57 and 13 percent respectively.

Refrences [1]http://www.space.com/14736-sunspots-sun-spots-explained.html [2] Arvind Bhatnaga Why Study the Sun?, J. Astrophys. Astr. 27 (2006), 59–78 [3] A.B. Galvin et al, Space Sci Rev (2008) 136: 437–486, [4] Meir H Degani,Astronomy Made Simple, main street books,October 12,(1976) [5] W. X. Wang, L. Li and Z. Yuan, IEEE, vol. 6, pp. 446-449, (2006) [6] J.C. Riaño-Rojas, E. Restrepo-Parra, F.A. Prieto-Ortiz and J.J. Olaya-Florez, Superlattice Microst., vol. 43, pp. 564-569, (2008). [7] A. B. Flores, L. A. Robles, M. O. Arias and J. A. Ascencio , Micron vol. 34, pp. 109-118, (2003) [8] Y. P. Raizer, Gas Discharge Physics, Springer-Verlag, (1987) [9] Ahmad Salar Elahi, Mahmood Ghoranneviss, Journal of Fusion Energy (2011) [10]S LEE, Proceedings of IPFS Conference – The Plasma Focus – Enhancing Knowledge and Application Potentials,(2012) ,Bangkok [11] Abhisek Kodal,Soham Majumder, Utpal Deka, International Journal of Computer Applications® (IJCA) [12] Robert T.dixon,Dynamic astronomy sixth addition,prentice-hall,(1992)

1

[email protected]

PROBING THE ACCRETION INDUCED COLLAPSE OF WHITE DWARFS IN BINARY MILLISECOND PULSARS Ali Taani*1 *

Applied science department, Aqaba University college, Aqaba, Al-Balqa’ Applied University, P.O. Box 1199, 77110 Salt, Jordan

The Recycling process is usually considered as a standard model to produce Millisecond Pulsars (MSPs). I discuss another possible channel involving the Accretion Induced Collapse (AIC) of a white dwarf (WD) in binaries. As accreting binaries lead to orbit circularization due to tidal coupling during the accretion phase, Low-Mass X-Ray. Binaries (LMXBs) are considered to be the progenitors of MSPs. For this task, I present a model that attempts to turn binary MSPs into wide binaries with circular orbits (in Galactic disk and globular cluster) through the asymmetric kick imparted to the pulsar during the AIC process, which may indicate a sizeable kick velocity exceed (∼ 50 – 150 km/s) along the rotation of the protoneutron star. This can result due to the effect of shock wave, binding energy plus the mass loss (0.2M⊙). If the system survives, the resulting system typically has long circular orbit orbit (e < 0.1). Or it may disrupt the system and create a single MSP.

1

Email : [email protected]

Resolving the High Energy Universe with Strong Gravitational Lensing Anna Barnacka Harvard University, 60 Garden Street, 02138 Cambridge, MA, USA Extragalactic jets are the largest particle accelerators in the universe. They transport energy from regions close to supermassive black hole up to hundreds of thousands of light years into intergalactic space. They produce radiation from radio frequencies up to very high energy gamma rays. Despite their broad implication for high energy astrophysics, galaxy formation, and cosmology, the physical nature and internal structure of these jets remain essentially unknown. Our ability to study high energy emission from these extragalactic jets is severely limited by a poor angular resolution (0◦ .1 deg) of gamma-ray instruments: to resolve gamma-ray emission from even the nearest extragalactic jet Messier 87, the angular resolution would have to be improved by a factor of 1000. Most jets are much further away. Spatially imaging any jets will remain impossible for the foreseeable future. To overcome the technological limitations of gamma-ray instruments, I have proposed to investigate the gravitationally lensed sources [1,2]. Extragalactic jets are gravitationally lensed when a massive galaxy lies along the line of sight between the jet and the observer. The gravitational field of the galaxy deflects light on its way to us and acts as a lens, which both magnifies the emission, and also produces multiple mirage images of the source. Each of the multiple images travels through different lengths and different gravitational potential. The cosmic lens does not change the intrinsic variability of the source but introduces time delays. These time delays depend on the position of the source relative to the cosmic lens, and can be used to study the spatial structure of jets. The Large Area Telescope onboard the Fermi mission (Fermi/LAT [3]) continuously detects gammaray radiation from extragalactic jets. Fermi/LAT scans the entire sky every few hours providing an ideal set of data for measuring time delays. Among sources detected by Fermi/LAT, PKS 1830-211 and B2 0218+35 are gravitationally lensed. I analyzed active periods of PKS 1830-211. For two of these periods the emission is consistent with origination from the radio core, and for the other two the emission region is displaced from the radio core by more than ∼1.5 kpc. The result of temporal analysis combined with the properties of the lens from radio observations yield an improvement in spatial resolution at gamma-ray energies by a factor of 10,000 [4]. On August of 2012 the second source B2 0218+35 underwent a vigorous outburst of gamma-ray activity. The temporal analysis combined with the model of the lens shows that this gamma-ray flare does not spatially coincide with radio emission, as is commonly assumed [5]. The offset between the radio and gamma-ray emission challenges our understanding of particle acceleration mechanisms. Moreover, the offset indicates that attempts to use variable quasars to measure the Hubble constant, expressing the expansion of the universe, may be misguided. The coming era of time domain astronomy will provide well-sampled data for thousands of gravitationally lensed variable sources identified with Euclid, SKA, and LSST. The large ensemble of time delays will allow statistical investigation of the origin of emission from extragalactic jets, and will shed new light on our understanding of processes responsible for particle acceleration at large distances from supermassive black holes. References 1. 2. 3. 4. 5.

A. Barnacka, et al., ApJ, vol. 788, p. 139, Jun. 2014. A. Barnacka, et al., ApJ , vol. 799, p. 48, Jan. 2015. W. B. Atwood, et al., ApJ, vol. 697, pp. 10711102, Jun. 2009. A. Barnacka, et al., ApJ , vol. 809, p. 100, Aug. 2015. A. Barnacka, et al., ApJ , vol. 821, p. 58, Apr. 2016.

ULTRA-VIOLET IMAGING TELESCOPE ON ASTROSAT: EARLY RESULTS ON STARS AND STAR CLUSTERS A. Subramaniam∗1 , UVIT Science Team† *Indian Institute of Astrophysics, Koramangala II Block, Bangalore-560034, India † UVIT Collaboration I plan to present early results from the Ultra-violet Imaging Telescope (UVIT) onboard the ASTROSAT observatory. The UVIT instrument contains two 38-cm telescopes: one for the far-ultraviolet (FUV) region (130–180 nm); and the other for the near-ultraviolet (NUV; 200–300 nm) and visible (VIS) regions (320–550 nm) ranges; these are divided using a dichroic mirror for beam-splitting. UVIT is primarily an imaging instrument, simultaneously generating images in the FUV, NUV and VIS channels over a 280 -diameter circular field. Each channel can be divided into smaller pass bands using a selectable set of filters. CONFIGURATION OF UVIT IN ASTROSAT DOORS/SUN-SHIELDS

SECONDARY MIRROR

Baffles Tel.Tube PRIMARY MIRROR

Detector/filters

Cone

Figure 1: Schematic diagram of ASTROSAT and UVIT

WOCS 5885 -12

-14

-16

-18 3

3.5

4

4.5

5

log(Wavelength)

Figure 2: SED of a cadidate Blue Straggler+post-AGB/HB star along with the spectral models.

I plan to present early results on a Blue Straggler Star in NGC 188 and some results from the study of the globular cluster, NGC 1851. We report the discovery of a hot companion associated with one of the blue straggler stars (BSSs) in the old open cluster, NGC188. Using fluxes measured in four filters in UVIT’s Far-UV (FUV) channel, and two filters in the near-UV (NUV) channel, we have constructed the spectral energy distribution (SED) of the star WOCS-5885, after combining with flux measurements from GALEX, UIT, UVOT, SPITZER, WISE and several ground-based facilities. An analysis of the SED reveals the presence of a cool and hot components. We suggest that it is likely to be a Blue Straggler + post-AGB/HB star. We also report the UV colour Magnitude diagram of NGC 1851 as well as light curves of a few RR Lyrea stars. UVIT project is a result of collaboration between IIA, Bengaluru, IUCAA, Pune, TIFR, Mumbai, several centres of ISRO, and CSA. 1

Email: [email protected]

INFLATIONARY MAGNETOGENSIS IN R^2-INFLATION ON THE LIGHT OF PLANCK 2015 Anwar S AlMuhammad1 Qatif Astronomy Society – QAS 4101 – Alaujam, Unit No:1. SAFWA 32674, KSA We study the primordial magnetic field (PMF) generated by the simple model f^2 FF in Starobinsky, R^2-inationary model, the favorite model of planck 2015. The scale invariant PMF is achieved at relatively high power index of the coupling function, |α|~ 7.44. This model does not suffer from the backreaction problem as long as, the rate of inationary expansion, H, is less than the upper bound reported by Planck, 2015 ( H 3.6  105 MPl ) in the observable scales of wave numbers, kη. By using the scale invariant PMF generated by f^2 FF, we find that the upper limit of present magnetic field, B0  8.1  109 G . It is in the same order of PMF, reported by Planck, 2015.

References

1. A. AlMuhammad and R. Lopez-Mobilia, “Primordial Magnetic Fields in the f 2 FF Model in Large Field Inflation under De Sitter and Power Law Expansion”, Astronomical Notes AN, Vol.337, No.3, 318-328 (2016), DOI: 10.1002/asna.201512301, http://arxiv.org/abs/1601.02104. 2. A. AlMuhammad and R. Lopez-Mobilia, “Primordial Magnetic Field Generated in Natural Inflation” , General Relativity and Gravitation 47, 134 (2015), DOI:10.1007/s10714-015-19781, http://arxiv.org/abs/1505.04668. 3. AlMuhammad,” Inflationary Magnetogenesis in R2-Inflation after Planck, 2015” (in preparation), http://arxiv.org/abs/1505.05204

1

Email : [email protected]

Monitoring pulsating giant stars in M33: star formation history and chemical enrichment Atefeh Javadi* and Jacco Th. van Loon† *

School of Astronomy, Institute for Research in Fundamental Sciences (IPM), Tehran, 19395-5531, Iran † Lennard-Jones Laboratories, Keele University, ST5 5BG, UK

We have conducted a near-infrared monitoring campaign at the UK InfraRed Telescope (UKIRT), of the Local Group spiral galaxy M 33 (Triangulum). A new method has been developed by us to use pulsating giant stars to reconstruct the star formation history of galaxies over cosmological time as well as using them to map the dust production across their host galaxies. In first Instance the central square kiloparsec of M33 was monitored and long period variable stars were identified. We give evidence of two epochs of a star formation rate enhanced by a factor of a few. These stars are also important dust factories, we measure their dust production rates from a combination of our data with Spitzer Space Telescope mid-IR photometry. Then the monitoring survey was expanded to cover a much larger part of M33 including spiral arms. Radial star formation history profiles suggest that the inner disc of M33 was formed in an inside–out formation scenario. The outskirts of the disc are dominated by the old population, which may be the result of dynamical effects over many Gyr. We find correspondence to spiral structure for all stars, but enhanced only for stars younger than ∼ 100 Myr; this suggests that the spiral arms are transient features and not part of a global density wave potential. Here we present our methodology and describe results for the central square kiloparsec of M33 (Javadi et al. 2011 a,b, 2013) and the disc of M33 (Javadi et al. 2015, 2016). References 1. 2. 3. 4. 5.

Javadi A., et al., MNRAS accepted, (2016) Javadi A., et al., MNRAS, 447, 3973 (2015) Javadi A., van Loon J. Th., Khosroshahi H., Mirtorabi M. T., MNRAS, 432, 2824 (2013) Javadi A., van Loon J. Th., Mirtorabi M. T., MNRAS, 414, 3394 (2011) Javadi A., van Loon J. Th., Mirtorabi M. T., MNRAS, 411, 263 (2011)

ANALYSIS OD SUPER SUB-STORM EVENTS WITH REFERENCES TO POLAR CAP POTENTIAL AND POLAR CAP INDEX Binod Adhikari*1, Prashrit Baruwal†, Narayan P. Chapagain* *

Department of Physics, Patan M. Campus, Tribhuvan University, Patan Gate, Lalitpur. Nepal † Department of Physics, Amrit Science Campus, Tribhuvan University, Kathmandu, Nepal

For delinating the concept of the magnetosphere-ionosphere system, the coupling process between solarwind-magnetosphere-ionosphere is an important physical mechanism. In this work, we have studied the Polar Cap Potential (PCV) and Merging electric field (Em) during three different Supersubstorm (SSS) events. We have also studied the roles of polar cap index (PCI) and auroral electrojet (AE) indices to observe polarcap (PC) activity during SSSs. To substantiate results, wavelet transform and cross-correlation techniques are used. We checked, the crosscorrelation of PCV with AE, SYMH, Bz, X, Y and Ey individually. Positive good correlation of PCV with AE and SYM-H is obtained. Observing and obtaining these results, PCV shows the significant effects during geomagnetic activity (SSSs) generated by geo-effective solar wind parameters.

1

Email : [email protected]

MODELING TEMPORAL EVOLUTION OF EXTRAGALACTIC RADIO SOURCES C. I. Onah*, †1, A. A. Ubachukwu† and F. C. Odo†,** *

Department of Physics, Federal University of Technology, Owerri, Nigeria Department of Physics & Astronomy, University of Nigeria, Nsukka, Nigeria ** National Centre for Energy Research and Development, University of Nigeria, Nsukka, Nigeria †

Temporal evolution in the current sample of EGRSs is modeled in terms of the current inflationary model with Ω0 = 1 and z = 1. In the light of temporal evolution in EGRSs, the correlation between linear size and radio luminosity was investigated. A D – P plot for the sample of extended steep spectrum revealed that the ESSG and ESSQ were not equally represented in the D – P plane. The results suggested that there is a weak trend for the entire sample over all redshifts. However for high redshift sources (z ≥ 1), the linear size – radio luminosity anti-correlation is fairly significant with r ~ -0.6. Meanwhile for all sources at low redshift (z < 1), though the trend is weak, the D – P correlation revealed positive correlation as predicted in this work. The results revealed that the D – P turnover of EGRSs occurs at critical point of luminosity, log Pcrit = 26.33WHz-1 and log Dc = 2.51kpc (316.23 kpc). At P ≥ Pcrit, there is a remarkable strong anti-correlation of r ~ -0.7 compared to the weak correlation obtained at P < Pcrit, r ~ 0.21. The values for the temporal evolution, D ~ P-q yield q = +0.003 and -1.59 for z < 1 and z ≥ 1 respectively, while q = +0.29 and -0.53 for P < Pcrit and P ≥ Pcrit respectively. It was suggested that conflicting results on the size evolution of sources might be as a result of luminosity selection effect.

1

Email : [email protected]

REVISING THE TRANSIT DEPTH - METALLICITY CORRELATION OF KEPLER'S GIANT PLANETS: HIEARCHICAL BAYESIAN APPROACH Cyrine Nehmé1,2 , Paula Sarkis3 1

Notre Dame University, Lebanon (12-point, centred) CEA Saclay, DSM/Irfu/Sap (Astrophysics Division), 91191 Gif-sur-Yvette Cedex, France 3 Universität Bern Space Research & Planetary Sciences Division

2

Previous attempts to study the correlation between the transit depth and the stellar metallicity of Kepler's gas giant planets has lead to different results. [2] (DR12) reported a weakly significant negative correlation. DR12 studied the transit depth of giant planets from [1] (Q1-Q12) with estimated radii of 5-20R and the values of [Fe/H] taken from the Kepler Input Catalog (KIC). [6] found that the random errors on the (KIC) [Fe/H] values would prevent such correlation from being detected. With the release of the last Kepler catalog (Q1-Q17) [9], we now have relatively the largest homogeneous sample of exoplanets. This enables a solid statistical analysis of this correlation. In the present work, we revise this correlation from within a Bayesian framework for two samples: confirmed and complete. We expand the Hierarchical model of [8]to account for false positives in the studied samples. For both samples, we were not able to reproduce any correlation. We demonstrate that there is relatively large intrinsic scatter in the relation.(see Fig. 1)

Figure 1. The graphs are the transit depth (δ) of Kepler's giant planets vs the metallicity of the host star ([Fe/H]). The dashed red line represent the best fit line and the light red lines are samples from the MCMC chain. (Left is for the confirmed planets and right plot is for the complete sample) [1].

References !. Borucki, W. J., Koch, D. G., Basri, G., Batalha, N., et al. 2011, ApJ, 736, 19 2. Dodson-Robinson, S. E. 2012, ApJ, 752, 72 3. Farr, W. M., et al. 2014, arXiv:1412.4849 4. Fortney, J. J., & Nettelmann, N. 2010, Space Sci. Rev., 152, 423 5. Fressin, F., et al. 2013, APJ, 766, 81 6. Gaidos, E., & Mann, A. 2013, ApJ, 762, 41 7. Huber, D., et al. 2014, ApJS, 211, 2 8. Kelly, B. C. 2007, ApJ, 665, 1489 9. Mullally, F., Coughlin, J. L., Thompson, S. E., Rowe, J. et al. 2015, ApJS, 217, 31 Email : [email protected] [email protected]

THIN ACCRETION DISKS AROUND A ROTATING COMPACT OBJECT SURROUNDED BY QUINTESSENCE MATTER Edward Larranaga∗1 * National Astronomical Observatory. National University of Colombia Current astronomical observations of supernovas suggested that the Universe is undergoing an accelerated expansion. One of the many models used to explain this behavior is the existence of a dynamic scalar field known as quintessence [1]. This field has been incorporated by Kiselev [2] in a general static and spherically symmetric solution of the Einstein field equations which recovers Schwarzschild and Reissner-Nordstrom solutions as particular cases but which may represent a compact object surrounded with quintessence matter, described by an equation of state of the form p = ωρ with a state parameter in the range −1 < ω < − 31 [3,4]. Some general aspects of spherical accretion onto these static Kiselev black holes such as critical radius, critical fluid velocity and speed of sound has been presented in [5]. However, it is well known that thin disks are a better model of accretion in many astrophysical systems [6,7]. Therefore, in this work we study the equations describing the properties of a thin accretion disk around a recently reported rotating compact object surrounded by quintessence matter described by the metric given in [8] and [9]. Assuming a geometrically thin model and an α-prescription for viscosity [10], we use the relativistic hydrodynamics equations to obtain the structure of the disk. Then, considering that the energy transport is due principally to radiation we present a numerical calculation of the disk spectrum [11,12]. By comparison with the known description of thin disks, we show that quintessence matter may play an important role in the accretion. References 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12.

S. M. Carroll, Phys. Rev. Lett. 81, 3067 (1998) V. V. Kiselev, Class. Quan. Grav. 20, 1187 (2003) B. Majeed, M. Jamil, P. Pradhan. Adv. High Energy Phys. 2015, 124910 (2015) A. Younas, S. Hussain, M. Jamil, S. Bahamonde. Phys. Rev. D92, 084042 (2015) R. J. Yang, arXiv:1605.02320 [gr-qc] J. Frank, A. King and D. Raine, Accretion Power. Cambridge University Press. (1992) H. Riffert. Thin Accretion Disks around Black Holes. In: Relativistic Astrophysics (eds. H. Riffert et. al.). Vieweg+Teubner Verlag (2016) pp. 120-138. S. Ghosh, European Physical Journal C 76, 222 (2016) Z. Xu and J. Wang. arXiv:1609.02045 [gr-qc] N. I. Shakura and R. A. Sunyaev, Astron. Astrophys. 24, 337 (1973) I. D. Novikov and K. S. Thorne. Astrophysics of Black Holes. In: Black Holes (eds. C. DeWitt and B. S. De Witt). Gordon and Breach (1973) pp. 344 D. N. Page and K. S. Thorne, Mon. Not. R. Astron. Soc., 191, 499 (1974)

1

Email: [email protected]

Monitoring Survey of Pulsating Giant Stars in Local Group Galaxies Survey Description, Science Goals, Target Selection Saremi Elham 1,2*, Atefeh Javadi2, Jacco Th. van Loon3, Habib Khosroshahi2, Abbas Abedi1, James Bamber3, Seyed Azim Hashemi4, Fatemeh Nikzat5, Alireza Molaei Nezhad2 1

Physics Department, University of Birjand, Birjand 97175-615, Iran School of Astronomy, Institute for Research in Fundamental Sciences (IPM), Tehran, 19395-5531, Iran 3 Lennard-Jones Laboratories, Keele University, ST5 5BG, UK 4 Physics Department, Sharif University of Tecnology, Tehran 1458889694, Iran 5 Instituto de Astrofisica, Facultad de Fisica, Pontificia Universidad Catolica de Chile, Av. Vicuna Mackenna 4860, 782-0436 Macul, Santiago, Chile

2

Nearby dwarf galaxies in the Local Group make a complete galactic environment that is perfect for studying the connection between stellar populations and galaxy evolution. Accordingly, the study of their present status, their formation and evolution is of great importance. In this study, we have conducted an optical monitoring survey of 65 dwarf galaxies in Local Group with Isaac Newton Telescope (INT) to identify long period variable stars (LPVs). These stars are at the end points of their evolution and therefore their luminosity can be directly translated into their birth mass; this enables us to reconstruct the star formation history [1]. We will obtain observations over ten epochs, spaced approximately 3 months apart, to assist in identifying long-period, dust-producing AGB stars; five epochs of data have been obtained already. LPVs are also the main source of dust; in combination with Spitzer Space Telescope images at midIR wavelengths we will quantify the mass loss [2], and provide a detailed map of the mass feedback into the interstellar medium. We will also use the amplitudes in different optical passbands to determine the radius variations of the stars, and relate this to their mass loss. References 1. A. Javadi, J.Th. van Loon, and M. T. Mirtorabi, MNRAS. 414, 3394 (2011). 2. M. L. Boyer et al, ApJS. 216, 10B (2015).

*

Email : [email protected]

ON THE OPTICAL–X-RAY CORRELATION FROM OUTBURST TO QUIESCENCE IN LOW-MASS X-RAY BINARIES F. Bernardini1, D. M. Russell1, K. I. I. Kolojonen1, L. Stella2, R. I. Hynes3, and S. Corbel4 1

New York University Abu Dhabi, P.O. Box 129188, Abu Dhabi, UAE; INAF-Osservatorio astronomico di Roma, Via Frascati 44, Rome, Italy; 3 Department of Physics and Astronomy, Louisiana State University, 202 Nicholson Hall, Tower Drive, Baton Rouge, LA 70803, USA; 4 Laboratoire AIM (CEA/IRFU—CNRS/INSU—Université Paris Diderot), CEA DSM/IRFU/SAp, F-91191 Gif-sur-Yvette, France 2

Transient low-mass X-ray binaries (LMXBs) show evidence of a global correlation of debated origin between X-ray and optical luminosity. Moreover, the population of BH systems as a whole is a factor of ∼20 optically brighter than the NS population at a given X-ray luminosity (Russell et al. 2006), in both outburst and quiescence, and the emission mechanisms responsible for this difference are still unknown. In this talk I will present our latest results (Bernardini et al. 2016) that are crucial to understand the physical reasons making black hole systems so different from neutron star systems from an observational point of view. We studied for the first time the X-ray and optical correlation in two transient LMXBs, the black hole V404 Cyg and the neutron star Cen X-4, over six orders of magnitude in X-ray luminosity, from outburst to quiescence. After subtracting the contribution from the companion star, the Cen X-4 data can be described by a single powerlaw correlation of the form Lopt ∝ LX0.44, consistent with disk reprocessing. We find a similar correlation slope for V404 Cyg in quiescence (0.46) and a steeper one (0.56) in the outburst hard state of 1989. However, V404 Cyg is about 160–280 times optically brighter, at a given 3–9 keV X-ray luminosity, compared to Cen X-4. This ratio is a factor of 10 smaller in quiescence, where the normalization of the V404 Cyg correlation also changes. Once the bolometric X-ray emission is considered and the known main differences between V404 Cyg and Cen X-4 are taken into account (a larger compact object mass, accretion disk size, and the presence of a strong jet contribution in the hard state for the black hole system), the two systems lie on the same correlation. In V404 Cyg, the jet dominates spectrally at optical–infrared frequencies during the hard state, but makes a negligible contribution in quiescence, which may account for the change in its correlation slope and normalization. These results provide a benchmark to compare with data from the 2015 outburst of V404 Cyg and, potentially, other transient LMXBs as well. I will provide accurate details on how to generate a universal plot (including new data from other LMXBs and from new outbursts of V404 Cyg and Cen X-4) that allows to properly comparing all black hole and neutron star systems finally unveiling the differences in their emission mechanisms. References 1. Russell et al. 2006, MNRAS, 371, 1334 2. Bernardini et al. 2016, ApJ, 826, 149 ________________ 1 Email: [email protected]

NEW METALLIC LINE DOUBLING AND VAN HOOF EFFECT IN THE SPECTRA OF THE VARIABLE RR LYRAE STAR F.L. Sefyani1, A. Benhida1, Z. Benkhaldoun2, T. De France3, D. Gillet4, P. Mathias5,6, M. Lazrek2, Y. Eljariri2, K. Chafouai2, A. Daassou2 1

Oukaïmeden.Observatory. LPHEA. FSTG. Cadi Ayyad University. BP 618 Marrakech. Morocco. e-mail: [email protected] 2 Oukaïmeden Observatory. LPHEA. FSSM. Cadi Ayyad University. BP 2390 Marrakech. Morocco. 3 AAVSO (American Association of Variable Star Observers), 49 Bay State Rd, Cambridge, MA 02138, USA. 4 Observatoire de Haute-Provence - CNRS/PYTHEAS/Université d’Aix-Marseille, 04870 Saint Michel l’Observatoire, France. 5 Université de Toulouse, UPS-OMP, Institut de Recherche en Astrophysique et Planétologie, Toulouse, France 6 CNRS, UMR5277, Institut de Recherche en Astrophysique et Planétologie, 14 Avenue Edouard Belin, 31400 Toulouse, France. ABSTRACT

In this work, we present the observation of lines doubling absorption in the spectra of the RR Lyrae variable star on the metal lines of FeII (λ4923.921Ǻ). This phenomenon is also observed, for the first time, on the metallic lines of FeII (λ4549,214Ǻ), as well as of D1 and D2 lines of sodium [1-2]. For the emission, we observed the lines of hydrogen H and H with a very high intensity and the two lines of HeI (λ5875.66Ǻ and λ6678.15Ǻ) [3]. Besides, we detected for the first time the Van Hoof effect between the FeII (λ4549,214Ǻ) and the H line. During the expansion phase of the photosphere of the star and during the passage of the shock wave we witnessed a disappearance of the absorption lines of neutral FeI (λ4934.006Å and λ4920.503Å) and their reappearance in the phase 1.00 [4]. The emission line D3 HeI (λ5875.66Ǻ) is visible on four consecutive spectra for a period of 20 minutes [3-5-6]. This transmission / Helium I remission is directly related to the intensity of the shock wave through the atmosphere of the star during the phase of maximum Blazhko cycle. These observations were made with a spectrograph resolution scale about 12,000 installed on the C14 telescope at the Oukaïmeden observatory (J43) during the different star pulsation cycle. We noticed that some of them almost coincide with the maximum Blazhko cycle. Schwarzschild interpreted the doubling lines on the basis of a two-layer atmosphere. This interpretation could measure the speed of the shock wave derived from the difference between the two red and blue spectral components on H hydrogen lines, D3 helium, D1 and D2 lines of sodium and FeII during the observed doubling of lines. At phase 1.00, the shock wave reached the maximum speed of 160 km.s-1 confirming the hypersonic regime that is subdued atmosphere during this maximum Blazhko cycle. α

β

β

α

References : 1. M. Chadid and D. Gillet, A&A, 308, 481 (1996) 2. M. Chadid and D. Gillet, A&A, 319, 154 (1997) 3. D. Gillet, F.L. Sefyani, A. Benhida, N. Fabas, P. Mathias, Z. Benkhaldoun and A. Daassou, A&A. A134, 587 (2016) 4. M. Chadid, J. Vernin and D. Gillet, A&A, 491, 537 (2008) 5. G. W. Preston, A&A. 507, 1621 (2009) 6. D. Gillet, N. Fabas and A. Lèbre, A&A, A59, 553 (2013)

ON THE MORPHOLOGICAL DICHOTOMIES OBSERVED IN THE POWERFUL RADIO GALAXIES Halime Miraghaei*1 and Philip N. Best† *

School of Astronomy, Institute for Research in Fundamental Sciences, PO Box 19395-5531, Tehran, Iran † Institute for Astronomy (IfA), University of Edinburgh, Royal Observatory, Blackford Hill, EH9 3HJ Edinburgh,UK We study environment and host galaxy properties of powerful radio galaxies with different radio morphologies from compact sources to very extended double lobed radio galaxies and with different optical spectra as high excitation (HERG; quasar-mode) and low excitation (LERG; jetmode) radio galaxies. We use a complete sample of morphologically classified radio sources from NVSS and FIRST and the parent galaxy sample from the Sloan Digital Sky Survey (SDSS). We perform three different analyses: i) we compare compact radio sources with the extended sources from the same class of excitation. ii) then compare HERGs with the LERGs using a combined sample of compact and extended sources. iii) we investigate the origin of different morphologies observed in the very extended powerful radio galaxies, historically classified as Fanaroff–Riley (FR) radio galaxies of type I and type II by comparing a sample of FRIs with the FRIIs from the same excitation class. We discuss the results and what causes the differences in each comparison. The role of host galaxy and the central super massive black hole, and the galaxy interactions are all investigated.

1

Email : [email protected]

NEW ON THE SOLID CORE OF THE EARTH Hatam Guliyev1 Institute of Geology and Geophysics of Azerbaijan National Academy of Sciences, Ave. H. Javid 119, Baku, AZ 1143 Azerbaijan According to current scientific belief, internal structure of the Earth and the distribution of its basic parameters is of the form shown in Figure 1 [1-4]. It can be seen from figure that pressure level reaches a value that is significantly greater than the theoretical limit of medium strength at the surface of the sphere of the inner core. It is shown that the equilibrium state of the solid core of the Earth depending on the shape of modeling of surface loads is unstable on geometric forming, or "internal" instability occurs in it. In these cases, propagation of homogeneous deformations becomes uneven in the sphere. At the same time, the physical parameters of the medium are determined in the laboratory conditions on samples while maintaining uniform homogeneous deformations. Moreover, it is shown that the elastic waves with actual velocity can't propagate in such conditions in solid medium. Violation of these fundamental conditions of mechanics needed in determining the physical and mechanical properties of the medium must be taken into account in the integrated interpretations of seismic and laboratory (experimental) data. In this situation, application of linear theory of elasticity and elastic waves, despite compliance with the required integral conditions on the mass, moment of inertia and natural oscillations of the Earth, does not ensure the reliability of results on the structure and composition of the Earth's core. Thus, it is shown that the inner core of the Earth cannot exist in the form of a spherical structure in the assumed thermobaric conditions and calculation values of physico-mechanical parameters based on the basic principles of mechanics of deformable solids relating to the strength, stability and propagation of elastic waves.

Figure 1. Profiles of density distribution, velocities of sound waves in the Earth's core on PREM

model [1] and also the temperature [3] (a); scheme of the structure of the Earth's core reflecting the main results of the seismological researches (b). Figure 1 taken from [4]. References 1. A. M. Dziewonski, and D. L. Anderson, Phys. Earth Planet. Inter. 25, doi:10.17611/DP/9991844 (1981). 2. D. L. Anderson, New theory of the Earth. New York: Cambridge University Press (2007). 3. F. Nimmo, Energetics of the core. Oxford: Elsevier. 8, http://dx.doi.org/10.1016/B978-0-44453802-4.00139-1 (2015). 4. K. D. Litasov, and A. F. Shatskiy, Russian Geology and Geophysics 57 (1), doi:10.1016/j.rgg.2016.01.003 (2016). 1

Email : [email protected]

A SEARCH FOR EXTRAGALACTIC PULSARS IN THE LOCAL GROUP GALAXIES IC 10 AND BARNARD’S GALAXY Hind Al Noori1∗ , Mallory S.E. Roberts1,2 , David Champion3 , Maura McLaughlin4 , Scott Ransom5 , and Paul Ray6 1

New York University Abu Dhabi, Abu Dhabi, UAE 2 Eureka Scientific, Oakland, CA. USA 3 Max-Planck-Institut fr Radioastronomie, Bonn, Germany 4 West Virginia University, Morgantown, WV. USA 5 National Radio Astronomy Observatory, Charlottesville, VA. USA 6 Naval Research Lab, Washington, DC. USA As of today, an incredible number of pulsars (2500+) have been found [1], most of which are in the Milky Way, with the exception of 27 pulsars in the Small and Large Magellanic Clouds [2]. However, there have been few attempts to search for pulsars deeper in our galactic neighborhood. We use the Green Bank Telescope to search two of the more promising Local Group galaxies, IC 10 and NGC 6822 (also known as Barnard’s Galaxy) for pulsars. These galaxies were chosen primarily due to their relatively high star formation rate and their proximity to our galaxy. IC 10 in particular, holds promise as it is the closest starburst galaxy to us and harbors an unusually high number of Wolf-Rayet stars, implying the presence of many neutron stars [3]. Unfortunately, we fail to detect continuous pulsations from either of the two galaxies. This failure could be due to the sensitivity limits of current telescope technologies at the extragalactic distances required (IC 10 and NGC 6822 are 10x farther than the Magellanic Clouds). We also perform single pulse searches of both galaxies, which hold greater promise for detection as they are generally much stronger signals than continuous pulsations [4]. References 1. Manchester, R. N, et al. ”The Australia telescope national facility pulsar catalogue.” The Astronomical Journal 129.4 (2005): 1993. 2. Ridley, J. P., et al. ”Eight new radio pulsars in the Large Magellanic Cloud.” Monthly Notices of the Royal Astronomical Society (2013): stt709. 3. Massey, Philip, and Shadrian Holmes. ?Wolf-Rayet Stars in IC 10: Probing the Nearest Starburst.? The Astrophysical Journal Letters 580.1 (2002): L35. 4. McLaughlin, Maura A., and J. M. Cordes. ?Searches for giant pulses from extragalactic pulsars.? The Astrophysical Journal 596.2 (2003): 982.

1

Email: [email protected]

THE ENERGETIC PARTICLE DETECTOR (EPD) ON BOARD SOLAR ORBITER J. Rodríguez-Pacheco1, M. Prieto1, S. Sánchez1, R. Wimmer-Schweingruber 2, C. Martín2, G. Ho3 and G. Mason3 1

Space Research Group, University of Alcalá, Alcalá de Henares, Madrid, Spain 2 University of Kiel, Germany 3 Applied Physics Laboratory, Johns Hopkins University, USA.

The Energetic Particle Detector (EPD) is a suite of instruments to be flown on-board the Solar Orbiter (SolO) mission of the European Space Agency (ESA) in collaboration with NASA. SolO is the first medium class mission of ESA´s Cosmic Vision program and it will be launched in October 2018. The orbital closest perihelion will be 0,285 AU and thanks to several gravity assists manoeuvres with Venus it will reach an orbital inclination above 33º during the extended phase of the mission. SolO expected lifetime is 10 years. EPD consists of four sensors: STEP (Supra Thermal Electrons and Protons), SIS (Suprathermal Ion Spectrograph), EPT (Electron Proton Telescope) and HET (High Energy Telescope). It will measure electrons, protons, and ions from helium to iron at high cadence and in different pointing directions, and operating at partly overlapping energy ranges from 2 keV up to above 200 MeV/n. All the sensors have strong heritage from previous missions (improved and optimized for the close approach to the Sun) and share the Instrument Control Unit (ICU) that is the sole power and data interface of EPD to the spacecraft. (See Fig. 1).

Figure 1. EPD suite.

EPD will directly address the SolO top-level question: “How do solar eruptions produce energetic particle radiation that fills the Heliosphere? Which in turn can be split into several key topics, namely: SEP seed populations; Injection, acceleration and release processes of Solar Energetic Particles (SEPs) and SEP transport in the interplanetary medium. These topics are not only relevant to the heliospheric scientific community but are also common to the astrophysics community involved in the particle acceleration at shock waves in supernovae and some other violent phenomena in the Cosmos. The comprehensive measurements of the energetic particle population that EPD will make along with the closer distance to the Sun during perihelion will allow to disentangle the acceleration/injection processes from the transport in the Interplanetary Magnetic Field ones. Besides, SIS will provide the most complete information about the suprathermal population in the inner Heliosphere during the next decade. These are just two examples of the promising results that EPD will provide to the topics mentioned above. In this talk we will present EPD and give an overview of its contribution to the SEP questions that after years of investigation remain still open. References 1. Solar Orbiter Definition Study Report, ESA/SRE (2011) 14, (2011)

EFFICIENT IDENTIFICATION OF EXOPLANETARY TRANSIT SIGNALS Kamal Mohamed *†, Sabine Schindler†, Alaa Ibrahim*, Kareemaddin Maklad*, Ahmed Morsy* *

Physics of the Earth and Universe, Zewail City of Science and Technology, Giza, Egypt † Institute for Astrophysics, University of Göttingen, Göttingen, Germany

Throughout the last two decades, the search for extra-solar planets has been rapidly improving using direct and indirect methods of detection [1]. The transit is an indirect method that used in searching for extra-solar planets. Using the abilities of the recently advanced technologies in Photometry, the Kepler mission was launched in 2009 to observe more than 100,000 stars simultaneously and continuously. The high resolution light curves of more than 2000 interesting objects are available for detailed investigations. Here, we introduce a GUI (Graphical User Interface) for detecting true exoplanets signals, using the optimal BLS (Box-fitting Least Squares) algorithm. The GUI includes in one window the plots of: odd/even test, the spectrum of the BLS, the simple trapezoidal model plot, the time series light curve with in-transits, the phase folded light curve, and the X-Y Centroids. All these plots are interactive and the programmatic features in the GUI allow the user to easily change the period or the type of any candidate; consequently, these plots will change according to the user’s changes. These features facilitate the search for true signals and identifying false alarms. We tested the GUI with some known objects, and it shows faster and more accurate investigations, which is important for the next large scale search of planet candidates.

References 1.   Charbonneau, D., Brown, T. M., Latham, D. W. & Mayor, M. (2000) Detection of Planetary Transits Across a Sun-like Star. ApJ, 529, L45–L48.

Corresponding author: Dr. Alaa Ibrahim

[email protected]

Presenting author: Mr. Kamal Mohamed

[email protected]

RADIO ASTRONOMY IN ARAB WORLD K.A. Edris1 Al-Azhar University, Faculty of Science, Astronomy Dept., Cairo, Egypt Abstract Radio astronomy is the branch of astronomy which study the universe in the radio of the electromagnetic radiation. The radio observatories spread across many countries and nations. The cooperation in this field is too important to build a network of radio telescopes with multi dishes which allow more precise and resolved images of the astronomical objects. This way of observing the sky have not yet reached the arab world. In this article, the observing bands and observatories of the radio waves are reviewed and a proposal of introducing this branch of astronomy to the arab world is suggested.

Suggested arab radio network. each small white circle represent a proposed insulation of a single radio dish; these dishes altogether would form a network with angular resolution of 0.002 arcsecond.

Background There are many bands to observe the different astronomical objects and processes. Each band gives its unique view of the picture showing the related physical and chemical properties. Among these bands only optical and radio can be observed form the ground. Radio band offers a unique opportunity to study optically obscured regions and trace weakly emitting processes. The radio observatories spread across many countries and nations except the arabic countries. The collaboration in this field is essential due to the idea of interferometric technique of observation in addition to the great financial budget needed. Each observatory is working at certain frequencies/wavelengths. The way of observing has two main techniques of single dish surveys and high resolution interferometric studies. Single dish surveys examine the presence of the studied emission towards the objects of interest in low angular resolution while interferometric/array image the source of emission in high angular resolution which depends on the distance between the two most far telescope (see figure above). 1

Email: [email protected]

ASSESSMENT OF THE POTENTIAL OF THE NEW MOROCCAN TELESCOPE TRAPPIST-NORTH FOR HIGH-PRECISION EXOPLANET TRANSIT PHOTOMETRY Khalid Barkaoui*1, Michael Gillon†, Zouhair Benkhaldoun*, Jehin Emmanuel†, Thami Elhalkouj*, Ahmed Daassou* *

Oukaimeden Observatory, LPHEA, FSSM, Cadi Ayyad University † Institute of Astrophysics and Geophysics, University of Liege

TRAPPIST-North (TRansiting Planets and PlanetesImals Small Telescope) is a 0.6 m robotic telescope that has started operation at the Oukameden Observatory (Morocco) in June 2016. The project is led by the Origins in Cosmology and Astrophysics (OrCA) group at Liege University in Belgium [1]. TRAPPIST-North and its twin, TRAPPIST-South, installed in the Southern hemisphere in 2010 [2], are fully dedicated to the study of planetary systems via two complementary approaches: the detection and characterization of transiting exoplanets, and the study of comets and other small bodies in the Solar System. TRAPPIST team has announced they discovered three Earth-sized planets orbiting the dwarf star ’TRAPPIST-1’[5]. In this abstract we present, some examples of the observations we are carrying out with TRAPPIST-North. We choose to observe the transit of TrES3b a Hot-Jupiter.

Figure 1. Transit of TrES-3b observed on 01/06/2016 by TRAPPIST-North in the filter ’I+z’.

The observations, lasted for almost 3 hours on 01/06/2016, starting  1 hour before ingress and ending  0:73 hour after egress. TrES-3 has a magnitude J = 11:02, (1SWASPJ175207.01+373246.3) and we used an exposure time of 13 seconds. To analyze the transit light curve, we use the MCMC code (Markov Chain Monte Carlo) developed by Michael Gillon. The MCMC is a Bayesian inference method based on stochastic simulations that samples the posterior probability distribution of adjusted parameters for a given model [3]. TrES-3b is a Hot Jupiter with a very short orbital period (P = 1:30619 days) orbiting a G-type star (Teff = 5720150K). We measured a radius of 1.3464 .. and a mass of 1.9361 .. compared to 1.295 0.081 1.92 0.23 measured by the TrES team [4]. and References 1. http://www.orca.ulg.ac.be/TRAPPIST/ 2. E. Jehin et al., The Messenger 145, 2( 2011) 3. A. M. Gillon et al., A& A511, A3 (2010) 4. T. O. ’Donovan et al., ApJ 663, L37 (2007) 5. G. Michael Gillon et al., Nature 533, 221 (2016) 1

Email : [email protected]

GRAVITY AND THERMODYNAMICS: A NEW POINT OF VIEW IN THE ANALYSIS OF EQUILIBRIUM AND DYNAMICAL EVOLUTION OF GLOBULAR CLUSTERS Marco Merafina∗1 *Department of Physics, University of Rome La Sapienza, Italy In the analysis of the evolution of globular clusters, stellar encounters strongly contribute in phase space mixing of stellar orbits. In this scenario, thermodynamics plays a central role in the gravitational equilibrium and stability of the clusters, being binary relaxation time shorter than the age of such systems. On the other hand, the observations of luminosity profiles of globular clusters, at different values of the central gravitational potential, show self similar curves that suggested a unique sequence of models with the same distribution function and different parameters during the dynamical evolution [1]. This feature was also confirmed by several numerical simulations of globular clusters existing in literature. This means that the evolution of globular clusters can be studied by considering small thermodynamic transformations which keep constant the functional form of the velocity distribution of stars like in the framework of the Boltzmann statistical mechanics. Here we construct models with a different approach by applying thermodynamic principles to a Boltzmann distribution function with an Hamiltonian function which contains an effective potential depending on the kinetic energy of the stars, due to the effect of tidal interactions induced by the hosting galaxy. This particular form of the Hamiltonian function derives from solving the Fokker-Planck equation in a different way with respect to the King approach. The distribution obtained also corresponds to a maximum of the entropy, and therefore implies a thermodynamical equilibrium based on collisions among stars in the Fokker-Planck approximation. This result is a real breakthrough point in the analysis of dynamical evolution of globular clusters. We obtain new relations for the thermodynamical equilibrium in presence of a gravitational potential, a different form of the virial theorem, and introduce the concept of thermodynamic and kinetic temperature, pressure and chemical potential (the intensive quantities). In addition, we can show that a globular cluster can be described as a model containing regions with positive and negative specific heat producing thermodynamic instabilities which drive the systems towards the gravothermal catastrophe, without the necessity of an external thermal bath. The influence of the effective potential on the virial theorem will be described, together with the related consequences on the gravothermal stability limit for star clusters through the analysis of the caloric curve and its critical points. This new limit is different from one obtained by Katz in 1978 [2] and now is in complete accordance with the value related to the maximum of cluster distribution constructed by data from Harris Catalogue for globular clusters [3], solving the unexplained discrepancy evidenced since forty years. This agreement between theory and observations is obtained also for small clusters, giving the conditions for the disruption of clusters, never obtained from the theoretical point of view, but observed in several clusters. Finally, new developments on N-body simulations for glubular clusters are presented. The results confirm the presence and the predicted form of the effective potential arising from tidal interactions between the cluster and the hosting galaxy, as well the possibility to verify this effect by complete osservations of transverse and radial velocities of stars of a globular cluster even in one single shell at given radius. References 1. I.R. King, AJ, 71, 64 (1966). 2. J. Katz, MNRAS, 183, 765 (1978). 3. W.E. Harris, AJ, 112, 1487 (1996). 1

Email: [email protected]

PATTERN RECOGNITION IN SPECTRA OF STARS AND IN SPACE DATA M. Gebran*1 and F. Paletou†,** *

Department of Physics and Astronomy, Notre Dame University-Louaize, PO Box 72, Zouk Mikaël, Lebanon † Université de Toulouse, UPS-Observatoire Midi-Pyrénées, IRAP, 31000 Toulouse, France **CNRS, Institut de Recherche en Astrophysique et Planétologie, 14 av. E. Belin, 31400 Toulouse, France We present a new automated procedure that simultaneously derives the effective temperature Teff, surface gravity log g, metallicity [Fe/H], and equatorial projected rotational velocity ve sin i for stars. The procedure is based on the principal component analysis (PCA) inversion method, which is inspired by the work done on the solar polarised Stokes parameter profiles of a line split by the Zeeman effect in the presence of a magnetic field [1]. The efficiency and accuracy of this procedure have been proven for FGK [2,3], and late type dwarf stars of K and M spectral types [4]. Learning databases are generated from the Elodie stellar spectra library using observed spectra for which fundamental parameters were already evaluated or with synthetic data. The synthetic spectra are calculated using ATLAS9 model atmospheres. This technique helped us to detect many peculiar stars such as Am, Ap, HgMn, SiEuCr and binaries. This fast and efficient technique could be used every time a pattern recognition is needed. One important application is the understanding of the physical properties of planetary surfaces by comparing aboard instrument data to synthetic ones (e.g. [5]). References 1. 2. 3. 4. 5.

1

D. E. Rees, A. López Ariste, J. Thatcher, & M. Semel, M. A&A 355, 759 (2000) F. Paletou, T. Böhm, V. Watson, & J.-F. Trouilhet, A& A 573, A67(2015) M. Gebran, W. Farah, F. Paletou, R. Monier, & V. Watson, A& A 589, A83 (2016) F. Paletou, M. Gebran, E. R. Houdebine, & V. Watson, A& A 580, A78 (2015b) C. Bernard-Michel, S. Douté, M. Fauvel, L. Gardes, & S. Girard, Journal of Geophysical Research (Planets) 114, E06005 (2009)

Email : [email protected]

AL-WARDAT’S METHOD FOR ANALYZING CLOSE VISUAL BINARY STARS; THE ONLY WAY TO REVEAL THE SECRETS OF SUBGIANT STARS Mashhoor A. Al-Wardat* *

Dep. Of Physics Faculty of Science, Al al-Bayt University, Mafraq, 25113, Jordan

We emphasize on the importance of Al-Wardat’s Method in estimating the complete set of physical and geometrical parameters of sub-giant stellar binary systems. The method depends on obtaining the best fit between the entire observational spectral energy distribution (SED) of the system and synthetic SEDs created by atmospheric modelling of the individual components, consistent with the system’s modified orbital elements. The importance of studying sub-giant stellar systems arises from the following facts: sub-giant phase represents a short period of the lifecycle of a star, which means a small ratio of the galactic stellar systems, their close features to the main-sequence stars make it hard to distinguish between them, the difficulty to estimate the mass of a single star and hence to deduce its exact parameters, and the overlapping of the spectra of the components of a binary or a multiple stellar system which make hard to study each component alone. Several systems were analysed using Al-Wardat’s Method for analysing CVBS, among these there were three systems which discovered to host sub-giant components: HD25811 [1], HD375 [2] and HD6009 [3]. The positions of the components of the system HD6009 (Hip4809) is shown in Figure 1 as an example of the results.

Figure 1. The components of the CVBS HD6009 (Hip4809) on the evolutionary tracks of [4], which shows that both components are sub-giant stars with masses around 1.4M for each of them.

References [1] M. A. Al-Wardat, H. S. Widyan, and A. Al-thyabat, “Complex Analysis of the Stellar Binary HD25811: A Subgiant System,” Publ. Astron. Soc. Aust., vol. 31, p. 5, Jan. 2014. [2] M. A. Al-Wardat et al., “Speckle interferometric binary system HD375; Is it a sub-giant binary?,” Astrophys. Bull., vol. 69, pp. 58–66, Jan. 2014. [3] M. A. Al-Wardat, “Physical and geometric parameters of the evolved binary system HD 6009,” Astrophys. Bull., vol. 69, pp. 454–460, Oct. 2014. [4] L. Girardi, A. Bressan, G. Bertelli, and C. Chiosi, “Evolutionary tracks and isochrones for lowand intermediate-mass stars: From 0.15 to 7 M_sun, and from Z= 0.0004 to 0.03,” Astron. Astrophys. Suppl. Ser., vol. 141, no. 3, pp. 371–383, 2000.

THE REDSHIFT AND RECESSION VELOCITIES OF SUB- AND SUPERLUMINAL GALAXIES USING SPECTROSCOPIC MEASUREMENTS Mohamed Yousrya,1, Mariam Helmya, Alaa Ibrahima a

Zewail City of Science and Technology, Physics of the Earth and Universe, Giza, Egypt

We study the redshift and recession velocities of a number of galaxies with varying proximity to our Milky Way galaxy. We measure the redshift through the observed Hydrogen spectral line at 1215.6701 Angstrom (rest-frame) and/or by comparing the spectrum of the galaxy to the spectral cross correlation templates of the Sloan Digital Sky Survey (SDSS). Among the galaxies we studied are 3C 273, 3C 186, PKS 1127-14, 3C 298, [HB89] 1143-245, [HB89] 0237-233, HS1700+6416, 3C 48, and HE0450-2958. The recession velocity of each galaxy is calculated using relativistic Doppler effect with the observed range varying from 0.15 c to 1.43 c. We account for the observed superluminal recession velocities in the framework of special and general relativity and discuss the implications of our results to the evolution and fate of the universe.

1

Email: [email protected]

EFFECT OF MAGNETIC RECONNECTION IN STELLAR PLASMA Mostafa Hammoud *1, Mounib El-Eid*, and Marwan Darwish† *



Physics Department, American University of Beirut, Beirut 1107-2020, Lebanon Mechanical Engineering Department, American University of Beirut, Beirut 1107-2020, Lebanon

An important phenomenon in Astrophysics is the process of magnetic reconnection (MGR), which is envisaged to understand the solar flares, coronal mass ejection, interaction of the solar wind with the Earth’s magnetic field (so called geomagnetic storm) and other observations [1-3]. In addition, it plays a role in the formation of stars [4]. MGR involves topology change of a set of magnetic field lines leading to a new equilibrium configuration of lower magnetic energy. The MGR is basically described in the framework of the Maxwell equations linked to NavierStockes equations. Nevertheless, many details are still not understood. In this contribution, and for the aim to find evidence for MGR process to occur when resistivity takes place (Ohmic or non-Ohmic), we investigate the MGR in the framework of Magnetohydrodynamic (MHD) model of a single conducting fluid using modern powerful computational tool (Openfoam). Despite of the high conductivity of the plasma, resistivity becomes effective not due to collision processes, but because of sharp gradients of the magnetic field, which gives rise to the creation of a large current layer. The net effect is that tremendous magnetic energy is released and is converted to kinetic energy leading to heating and acceleration of charged particles [5]. The Sun’s coronal ejection is an example of the MGR.

References 1. E. N. Parker and M. Krook, ApJ 124, 214 (1956). 2. R. Kulsrud, Phys. Plasmas 5, 1599 (1998). 3. D. Biskamp, Magnetic Reconnection in Plasmas (Cambridge University Press, Cambridge) (2000) 4. E. Priest, and T. Forbes, Magnetic Reconnection—MHD Theory and Applications (Cambridge University Press, Cambridge) (2000). 5. M. Yamada, K.Russell, and J. Hantao. "Magnetic reconnection." Reviews of Modern Physics 82.1, 603 (2010).

1

Email : [email protected]

ON THE ACTIVITY OF THE NEAR AND FAR CIRCUMSTELLAR GAS IN SOME B[e] TYPE STARS N.Z.,Ismailov1, O.V.Khalilov, U.Z.Bashirova, S.A.Alishov Shamakhy Astrophysical Observatory of Azerbaijan National Academy of Sciences AZ5626, settl.Mamedaliyev, Shamakhy,Azerbaijan The phenomenon of B[e] stars is defined as the presence of low excitation forbidden emission lines, and an excess infrared radiation due to circumstellar dust in the spectra of hot stars. B[e] stars observed properties, unusual in many cases, challenge minds of astrophysicists and provide an invaluable material for further exploration of the Universe [1]. In this report is presents original results of spectral researches of Ae/Be Herbig type stars HD 200775, AB aur, IL Cep A, HD179218, and Be star 48 Lib. Spectral observations of program stars was carried out from June to September 2015 at the Cassegrain focus of 2 m telescope by using echelle spectrometer with resolution at 14000 and S/N relation ∼ 100 at the Hα and ∼ 10 at Hβ. In additionally for the analyses we have used results of our previous observations [2]. We have measured radial velocities and equivalent widths of emission lines Hα, Hβ, HeI λ 5876 Å, D1, D2 NaI, SiII λλ 6347, 6371 ÅÅ, [OI] λλ 6300, 6363 ÅÅ. For the star HD200775 first time in the spectra have discovered diffuse interstellar bands (DIBs) λλ 5780, 5797 ÅÅ. Our measurements are making it clear that for HD200775 the hydrogen emission lines Hα and Hβ have minimal values of equivalent widths with scatter at 20 - 30% around the mean value. Both of these lines are shown a double peaked structure where the intensity of emission components is variable. We have discovered considerable variations of the intensity in the blue wing of the emission Hα and in the red wing of emission Hβ. The lines [OI] λλ 6300, 6363 ÅÅ has a double peaked structure with variable relative blue to red V/R components intensities. For IL Cep A we have analyzed a structure of variability in the line HeI λ 5876 Å. On the analysis of the residual spectrum which was obtained by dividing the spectrum of IL CepA to the spectrum of the standard star HR 8029 with spectral class B2-3IV and rotational velocity vsini= 130 km/s we have discovered some additional radiation in the line. The maximum of intensity of the emission is observed in the maximal negative radial velocity hydrogen lines. It is showed that the hidden emission in the helium line shows a synchronic variability with the disk radiation of the star. For Be star 48 Lib from 2011 to 2015 radial velocities of the forbidden lines [OI] and DIB lines shows smooth variations from 0 to -40 km/s, while equivalent widths of this lines is decreased at 2 time. The trend of variations of radial velocities in the shell lines is occurred in inverse phase with the variations of hydrogen emission lines. This star has similar character with active B[e] type stars (mainly IR excess [3] and forbidden lines in the spectrum). In the HD 179218 we have discovered some seasonal variability in radial velocities and equivalent widths of hydrogen emission lines Hα and Hβ with typical characteric time of some ten days. The [OI] λ 6300 and 6363 ÅÅ lines and DIBs in the spectrum of the star is not discovered such variability. It is showed that a main active process is occurred in the inside of the disk of the star. For different stars the same character of variability we have obtained for lines [OI] and also for DIBs λλ 5780, 5797 ÅÅ. It is showed that active processes at the circumstellar environment of these systems can be influence of more far parts of the circumstellar disks. References 1. A. S.Miroshnichenko et al.,. ApJ. 809, 129M (2015). 2. N.Z.Ismailov et al., Astrophys.Bull. 68, 196 (2013). 3. I. McDonald, A. A. Zijlstra, M. L. Boyer, MNRAS, 427, 343(2012). _______________________________ 1 Email : [email protected]

INVESTIGATING THE GAMMA-RAY BURST – SUPERNOVA CONNECTION Nidhal Guessoum*1, Khalid Al-Qassimi1, Mohamed AlShamsi1, Alaa Yousef1, Nidal Sharif1, Hamid Hamidani2, Hannachi Zitouni3, Walid Azzam4 1

American University of Sharjah, UAE 2

University of Tokyo, Japan

3

4

Faculté des sciences, Université Dr Yahia Fares, Medea, Algeria Department of Physics, College of Science, University of Bahrain, Bahrain

Abstract Recent years have seen great progress in the study of gamma-ray bursts (GRBs), particularly with the huge amount of data provided by the Swift satellite, which is dedicated to GRBs, and other instruments, both in space and on the ground (optical afterglow followup, galaxy host identification, redshift measurement, etc.). And with the consensus that “long” GRBs, which make up about 90 % of all the bursts, are due to hypernovae (very big stars exploding as described by the collapsar model), the search for correlations between GRBs and supernovae has yielded surprising results, positive and negative detections, interesting correlations between some of the physical parameters, etc. We have undertaken a preliminary investigation of this topic, first searching the literature for the positive and negative cases, then comparing physical properties of GRBs for which associated supernovae have been detected and those of GRBs for which no supernovae were found after deep searches. For the two sub-samples, we have sought to compare the intrinsic GRB properties that are most related to the core-collapse event, i.e. duration, isotropic energy output, peak spectrum energy, etc., as well as properties related to the explosion and the environment, i.e. ejecta mass, velocity, metallicity, etc. We present preliminary results of our work, at least for the parameters that were available in the literature. We also point to future work on this topic, to be done by our group or others, particularly the study of the dependence (“evolution”) of various burst parameters and correlations (e.g. the Amati relation) with the redshift of the source, in the aim of trying to infer new insights on the physical conditions (and locations) of occurrence of (long) GRBs.         *

Email: [email protected]

ARE GIANT PLANETS BAD NEIGHBOURS FOR HABITABLE WORLDS? Nikolaos Georgakarakos*1, Siegfried Eggl†, and Ian Dobbs-Dixon* *



New York University Abu Dhabi, Saadiyat Island,Abu Dhabi,UAE Jet Propulsion Laboratory, California Institute of Technology, Pasadena,CA,USA

Today the existence of planets with comparable size to that of the Earth revolving around stars other than our Sun is an observational fact. An issue of great scientific as well as public interest is where Earth-like planets are likely to be found. A useful concept in this regard is the so-called habitable zone, defined as the region around a star where a planet with an Earth-like atmosphere on a circular orbit can support liquid water on its surface. In multiplanet systems the gravitational interactions between planets are capable of altering the orbits around the host star and therefore changing the amount of insolation each planet receives. As a result, the habitable zone limits are modified. In this work we quantify the actual insolation received by an Earth-like planet on its evolving orbit accounting for the presence of a giant planet in the same system. We find that a significant fraction of the giant exoplanets discovered so far radically reduce a terrestrial planet’s chances to remain within habitable radiation limits, even when their orbits are well separated. Moreover, we show that hot Jupiter systems may be the best suited to shelter habitable planets, if the latter survive the migration phase. In comparison with solar analogs, M-dwarfs with close in giant planets may be less likely to host habitable worlds.

1

Email : [email protected]

MAGELLANIC BRIDGE: AN OUTSTANDING LABORATORY TO TEST GALAXY FORMATION SCENARIOS Noelia E. D. No¨el ∗1 *Department of Physics, University of Surrey, Guildford, GU2 7XH, UK A key challenge in modern astrophysics is to understand how galaxies form and evolve. In particular, interactions between galaxies are an important driver of galaxy formation and evolution. These encounters reshape galaxies by transferring metals, gas, energy and mass between them, creating new sites of star formation both, within the galaxies and in between the stripped gas amidst them. Our closest irregular companions, the Small and Large Magellanic Clouds, located at 50 and 70 Kpc from us, offer the best workplace to study such interactions. I will present here the first unequivocal evidence, from spectroscopic and photometric data, of tidally stripped stars from the Small Magllenanic Cloud into the Magellanic Bridge, i.e. the bridge of HI gas and stars connecting both galaxies. I will discuss the impact this newly discovered stripped population has for galaxy formation and evolution processes.

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Email: [email protected]

A NEW MECHANISM TO SOLVE THE ULTRA HIGH ENERGY COSMIC RAYS GZK LIMIT N.Mebarki*1 and M.L.Abdelali† *

Laboratoire de Physique Mathématique et Subatomique, Frères Mentouri University, Constantine1, Constantine, Algeria † Laboratoire de Physique Mathématique et Subatomique, Frères Mentouri University, Constantine1, Constantine, Algeria

In this contribution, we investigate a new effect contributing to the total observed redshift of galaxies. The extra new redshift does not result from the universe expansion or the peculiar motion of galaxies. It is due to the photon radiation of high frequency gravitational waves in an external magnetic field. This effect will serve as an additional recalibration of the cosmological parameters improving our understanding to the universe and help to solve the ultra high energy cosmic rays (UHECR) GZK limit. As an application, this effect can be an explanation of some anomalous redshift such as: Stephan Quintet the compact interacting galaxy group, the galaxy-quasar associations and the discordant redshifts of some types of galaxies [1-2]. We have found that in all the above mentioned cases, a relation between these anomalous redshifts and the existence of strong sources of magnetic field supporting the nature of our non cosmological redshift. Other implications are possible observational measurement contamination. Several models predict a primordial cosmic magnetic field from the inflation, given a possible primary and secondary CMB anisotropies can be from the non cosmological redshift origin. The redshift observations of the Supernovae SN Ia have to be amplified by this effect. These two possible observational measurement contaminations affect the cosmological parameters estimations through CMB and SN Ia measurements. The observational measurements of the cosmic magnetic field by the Faraday rotation [3] have to consider this effect and reconsider the actual measured magnetic fields and electron densities of galactic and intergalactic medium. Thus, non cosmological contribution will account for the recalibration of Hubble parameter and the dark matter content of galaxies and clusters. Regarding the UHECR, according to the distance of their sources cutoffs are indicated by the threshold energy of interaction calculated from kinematics. These cutoffs change from a particle type to another and the various possible interactions e.g. for protons and taking into account its interaction with CMB photons, cutoff is about 50EeV for a mean free path of 50Mpc. GZK cutoff problem comes from the observation of events with energy greater than the cutoff energy knowing that we have not identified any possible sources within this estimated maximal distance. Distances of these possible sources are much greater than this maximum. Our explanation to this problem is that the source distance is computed from the redshift indicator that is not accurate The observed redshift is a composition of a cosmological and a non cosmological redshifts and does not reflect an accurate indicator of distances without extraction of amplification due to non cosmological effect. The Observed distances are greater than the cosmological ones and make objects to appear mistakenly more distant than they are really. For the numerical results and simulation, we have modified the old CRPropa software in a new one baptized RPC taking into account the non cosmological redshift effects on cosmological and observed distances.

References 1. P. Galianni at al, Astrophys.J. 620, (2005). 2. E. O'Sullivan et al, Astrophys.J . 701, (2009). 3. C.D. Mc Grasso and H.R. Rubinstein, Physics Reports 348, (2001)

FIRST ASTRONOMICAL SITE TESTING IN BENI MELLAL BY USING SATELLITE DATA Z. Ihsane*,1, E. A. Siher*, A. Salhi*, and Z. Benkhaldoun† *

Faculté des Sciences et Techniques, Département de Physique, BP 523 Béni Mellal, Morocco † LPHEA,Faculté des Sciences, Semlalia Marrakech, Morocco

We use the MODIS (Moderate Resolution Imaging Spectroradiometer) satellite data to compare tree sites in Beni Mellal region to the Oukaimeden Observatory (Marrakech). Those sites, located at on the middle Atlas Mountain, are not far from the University of Beni Mellal by good roads. First results show that our sites are qualified to install some astronomical instruments. In the following figure, we present an example of this comparison.

Figure 1. Meteorological comparison between our site (plus) and Oukaimeden Observatory (dot).

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Email : [email protected]

INVESTIGATING THE ORIGIN OF HIGH-ENERGY COSMIC-RAY ELECTRONS WITH MONTE CARLO SIMULATION Reda Attallah1 Badji Mokhtar University, Physics Department, P. O. Box 12, Annaba 23000, Algeria Due to severe radiative energy losses during propagation, high-energy cosmic-ray electrons can reach Earth only from nearby sources. Although these sources clearly manifest themselves in the puzzling features of the energy spectrum observed by recent space-borne experiments, especially the increase in the positron fraction, their exact nature is still a matter of debate. The standard method for interpreting cosmic-ray electron data consists in solving appropriate transport equations. It can be supplemented with a Monte Carlo approach taking advantage of the intrinsic random nature of cosmic-ray diffusive propagation. This analysis gives useful information on the electron-by-electron fluctuations and hence allows to address the issue from a different angle. Here we show how to implement a fully three-dimensional time-dependent Monte Carlo simulation of the propagation of high-energy cosmic-ray electrons from nearby sources and discuss the ”single-source” astrophysical scenario. References 1. 2. 3. 4. 5.

O. Adriani et al., Nature 458, 607 (2009). M. Ackermann et al., Phys. Rev. Lett. 108, 011103 (2012). M. Aguilar et al., Phys. Rev. Lett. 110, 141102 (2013). I. Cholis and D. Hooper, Phys. Rev. D 88, 023013 (2013). P. Picozza and L. Marcelli, Astropart. Phys. 53, 160 (2014).

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Email: [email protected]

SEARCHING FOR COMPTON-THICK AGNS WITH XMM-NEWTON OBSERVATIONS Reham Mostafa*★1, Matteo Guainazzi†, Alaa I.Ibrahim★ *

Department of Physics, Faculty of Science, Fayoum University, PO Box 63514, Fayoum, Egypt ★Physics †

of the Earth and Universe, Zewail City of Science and Technology, Giza, Egypt European Space research and Technology Centre, Keplerlaan 1 2201AZ Noordwijk, The Netherlands

Most Active galactic nuclei (AGNs) are obscured by large column densities of cold and neutral gas. If the X-ray obscuring matter has a column density equal to or larger than the inverse of the Thomson cross-section (NH ≥ σT ≈ 1.5×1024 cm-2), then the source is identified as a Compton-thick AGN. One of the characteristics of Compton-thick AGN is the presence of Fe k-α emission line in their spectra with a large equivalent width. Using this criterion with XMM-Newton observations we identified Compton-thick AGNs by following a selection method, FLEX algorithm, developed by [1] to search for X-ray line emitting objects (XLEOs). This technique detects the sources having significant excess of counts resulting from the iron emission line. Here we present the results from applying this method on the 28 highly absorbed AGNs recently detected by [2]. Of these 28 AGN, 15 are candidate Compton-thick AGN. We applied the detection algorithm on a pilot sample of 41 XMM-Newton observations. Our results confirm the Compton-thick nature of 12 of Compton-thick AGN, based on the observed properties of the Fe k-α emission line. We use the characteristics of the observed lines to diagnose the AGNs and their environments. References 1. Maccacaro T. et al., ApJ 617, L33-L36 (2004). 2. Corral A. et al., A&A. 569 (2014).

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Email: [email protected]

THE X-RAY SPECTRUM OF THE BLACK HOLE CANDIDATE SWIFT J1753.5−0127 Reham Mostafa1,4*, Mariano Mendez2, Beike Hiemstra2, Paolo Soleri2, Tomaso Belloni3, Alaa I. Ibrahim4 and Mohammed N. Yasein1

1 2

Department of Physics, Faculty of Science, Fayoum University, PO Box 63514, Fayoum, Egypt Kapteyn Astronomical Institute, University of Groningen, PO Box 800, 9700 AV Groningen, the Netherlands 3 INAF–Osservatorio Astronomico di Brera, Via E. Bianchi 46, I-23807 Merate (LC), Italy 4 Physics of the Earth and Universe, Zewail City of Science and Technology, Giza, Egypt

We present a spectral analysis of the black hole candidate (BHC) and X-ray transient source SWIFT J1753.5-0127, making use of simultaneous observations of XMM-Newton and Rossi X-ray Timing Explorer (RXTE) in 2006, when the source was in outburst. The aim of this work is to study the Xray continuum spectrum of SWIFT J1753.5-0127, to investigate the nature of radiation processes in the low/hard state, and further to test the presence of a soft component due to the accretion disc in the X-ray spectrum. We first fit the data with two models (POWER-LAW and COMPTT) describing the Comptonization of soft X-ray photons off the relativistic electrons in the surrounding corona. We further model the broadband spectrum with reflection component (REFLIONX, PEXRAV, and PEXRIV) to account for reflection of hard X-ray photons off the relatively cold accretion disc. We fit the data with a range of spectral models, and we find that for all of these models the fits to the X-ray energy spectra significantly require the addition of the disc black-body component, in consistent with result of a previous analysis of the same source (Miller et al. 2006). We also find a broad iron emission line at around 6.5 keV, most likely due to iron in the accretion disc. The fits of the X-ray broadband continuum is found to show an equally good description of the data in terms of the reduced χ2. Our results confirm the existence of a cool inner disc extending near or close to the innermost circular orbit (ISCO). We further discovered broad emission lines of N VII and O VIII at ∼0.52 and 0.65 keV, respectively, in the RGS spectrum of Swift J1753.5−0127.

References 1. Miller, J. M., Homan, J., Miniutti, G., ApJ 652, L113-L116 (2006).

*

Email: [email protected]

Reconstructing the Distortion Function for non-local gravity K. Yoosefi*, R. Pazhouhesh1* and D. Mota†

*. Physics department, University of Birjand, Birjand, Iran †. Institute of Theoretical Astrophysics, University of Oslo, Postboks 1029, 0315 Oslo, Norway

We develop Maggiore and Mancarella model [1] by replacing

£

term with

£

. We

used Woodard and Deffayet technique [2] to find distortion function. We want to reproduce ΛCDM cosmology with the same matter content [3]but a vanishing cosmological constant. We also make a Fortran code to solve coupled differential equations numerically and we find a polynomial function for this. We showed distortion function in Fig. 1.

Figure 1. Reconstruction function ( ) vs ( ) =

£

References [1] M. Maggiore and M. Mancarella, Phys. Rev. D 90 (2014) 023005 [arXiv:1402.0448 [hep-th]]. [2] C. Deffayet and R. P. Woodard. JCAP 0908 (2009) 023 arXiv:0904.0961 [gr-qc] [3] P.A.R. Ade (Cardiff U.) et al. A&A. 594 (2016) A13 arXiv:1502.01589 [astro-ph]

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Email : [email protected]

STABILITY OF EXOPLANETS ORBITING BINARY STAR SYSTEMS Roberto Capuzzo-Dolcetta*, Giovanni De Cesare1 *

Dep. of Physics, Sapienza, University of Roma, Italy 1

INAF-IASF, via. P. Gobetti 101, Bologna, Italy

A large number of exoplanets are discovered in binary star systems in inner or in circumbinary orbits. A review and an updated catalog is provided by Schwarz [1]. Wether the planet can be habitable depends on the possibility to maintain liquid water on its surface, and therefore on the luminosity of its host stars and on the dynamical proprieties of the orbit. To fully describe the motion of the planet, we would need a solution of the classical three body motion, but it is well known that this system is not integrable, also in the case where the mass of the planet is negligible with respect to the two stars, the so called restricted three-body problem. In this context a basic question is to evaluate if the planetary orbit is stable, in particular if the planet does not collide with one of the two stars or is ejected far away from the system. In this work, using a numerical approach and considering the realistic case of a non-zero mass planet, we evaluate how the stability of the orbits depends on the initial ellipticity and inclination of the planetary orbit. Some preliminary results on this topic have been presented at the international conference “Exoplanets in Lund 2015” (see [2]).

Figure 1. Sketch of the two main types of planet orbits around a binary star system. P orbits are around the pair while S orbits are around one of the 2 stars. (from [1]). References

1. http://www.univie.ac.at/adg/schwarz/multiple.html 2. http://www.astro.lu.se/lundexoplanets2015/slides

BeePol: An Imaging Polarimeter for the FMR Observatory Bachar Wehbe†∗ , Roger Hajjar† 1 †

Department of Physics & Astronomy, Notre Dame University-Louaize, Lebanon Centro de Astrofisica, University of Porto, Portugal

BeePol is an imaging polarimeter designed for the 60-cm telescope of the Farid & Moussa Raphael Observatory (FMRO) at Notre Dame University Louaize (NDU). It is based on the IMPOL polarimeter (Ramaprakash, 1998), with the introduction of a Wedged Double Wollaston prism (WeDoWo) as described by Oliva (1997), allowing for the simultaneous measurement of the I, Q, and U stokes parameters. When coupled to an Apogee Alta F42, 2k× 2k back illuminated, thinned, CCD camera, the polarimetric module allows for polarimetric imaging of a 1.220 × 230 field of view. Calculations done for the observing conditions at the FMRO show that the instrument may detect 1 We recently received funding to begin construction and testing of the instrument. Optical parts are being ordered, for lab mounting and texting of BeePol on an optical bench. The body of the instrument will be built locally. We expect first light in late spring or early summer 2016. BeePol aims to become a relatively inexpensive imaging polarimetry solution for small observatories. References 1. Oliva, E. 1997, A& AS, 123, 589 2. Ramaprakash, A.N., et al 1998, A& A, 128, 369 3. Wehbe, B., 2015, BeePol: An Imaging Polarimeter for the Farid & Moussa Rapahel Observatory, MS Thesis, Notre Dame University Louaize

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Email: [email protected]

The Farid & Moussa Raphael Observatory Roger Hajjar 1 Department of Physics & Astronomy, Notre Dame University-Louaize, Lebanon The Farid & Moussa Raphael Observatory (FMRO) at Notre Dame University Louaize (NDU) is an teaching, research, and outreach facility located at the main campus of the university. Although located very close to the Lebanese coast, in an urbanized area, it is currently the largest fully functional, and best equipped, observatory in the Arab Middle-East. It features a 60-cm Planewave CDK telescope, and instruments that allow for photometric and spetroscopic studies. The observatory currently has one thinned, back-illuminated CCD camera, used as the main imager along with Johnson-Cousin and Sloan photometric filters. It also features two spectrographs, one of which is a fiber fed echelle spectrograph. These are used with a dedicated CCD. The observatory has served for student projects, and summer schools for advanced undergraduate and graduate students. It is also made available for use by the regional and international community. The control system is currently being configured for remote observations. A number of long-term research projects are also being launched at the observatory.

1

Email: [email protected]

STAR FORMATION HISTORY OF NGC 147 AND NGC 185; USING LONG PERIOD VARIABLE STARS COUNT Roya H. Golshan*, †1, Atefeh Javadi*, Jacco Th. van Loon& *

School of Astronomy, Institute for Research in Fundamental Sciences (IPM), Tehran, 19395-5531, Iran † Department of Physics, Isfahan University of Technology, Isfahan, 84156-83111, Iran & 3Lennard-Jones Laboratories, Keele University, ST5 5BG, UK

NGC 147 and NGC 185 are two of the most massive satellites of the Andromeda galaxy (M 31). With similar mass and morphological type, they possess different amounts of interstellar gas and tidal distortion. The question therefore is, how do their histories compare? We present the first reconstruction of the star formation histories of NGC 147 and NGC 185 using long-period variable stars (LPVs). LPVs are low- to intermediate-mass stars at the asymptotic giant branch, which their luminosity is related to their birth mass. Combining near-infrared photometry with stellar evolution models, we construct the mass function and hence the star formation history. For NGC 185 we found that the main epoch of star formation occurred 8.3 Gyr ago, followed by a much lower, but relatively constant star formation rate. In the case of NGC 147, the star formation rate peaked only 7 Gyr ago, staying intense until ~ 3 Gyr ago, but no star formation has occurred for at least 300 Myr. Despite their similar masses, NGC 147 has evolved more slowly than NGC 185 initially, but more dramatically in more recent times. This is corroborated by the strong tidal distortions of NGC 147 and the presence of gas in the centre of NGC 185. References 1. Javadi A., van Loon J. Th., Mirtorabi M. T., 2011, MNRAS, 414, 3394 2. Javadi A., van Loon J. Th., Khosroshahi H. G., Tabatabaei F., Golshan R. H., Rashidi M., 2016, MNRAS, accepted 3. Golshan R. H., Javadi A., van Loon J. Th., Khosroshahi H. G., Saremi E., 2016, MNRAS, submitted

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Email : [email protected] / [email protected]

TRANSVERSE THERMAL INSTABILITY OF PARTIALLY-IONIZED PLASMA WITH HALL EFFECT AND FLR CORRECTIONS FLOWING THROUGH POROUS MEDIA FOR MOELECULAR CLOUD FORMATION IN ISM Sachin Kaothekar*1 *

Department of Physics, Mahakal Institute of Technology and Management, Ujjain, M.P. - 456664, India

The problem of thermal instability and radiative instability is investigated for partially ionized plasma which has connection in astrophysical condensations and formation of objects. A general dispersion relation has been derived with the help of relevant linearized perturbation equations, using the normal mode analysis method. Effects of FLR corrections, radiative heatloss function and collisions with neutrals on the thermal instability criterion of the system are discussed. The conditions of instability are derived for a temperature-dependent and densitydependent heat-loss function with thermal conductivity and FLR corrections for some special case. The stability of the system is discussed by using Routh-Hurwitz’s criterion. Numerical calculations have been performed to discuss the dependence of the growth rate of the thermal instability on the various physical parameters. The FLR corrections, porosity, magnetic field, and neutral collision have stabilizing influence while finite electrical resistivity has a destabilizing influence on the growth rate of the thermal instability. Our results are helpful for understanding the formation of molecular clouds in ISM.

1

Email : [email protected]

A Variability Study of the Black Hole Candidate Swift J1753.4-0126 Salama Al-Hinai*, Zach Ioannou*1, Antonios Manousakis† *

Department of Physics, College of Science, Sultan Qaboos University, Muscat, Oman † N. Copernicus Astronomical Center, Warsaw, Poland

We present preliminary results from a variability study of the black hole candidate system Swift J1753.5-0123. The system exhibits an orbital period of 3.24 hours, one of the shortest orbital periods for a black hole binary candidate. The system is known for the exceptionally long time it took to return to a quiescent state. Our current analysis utilises data from the XMM, Swift and NuSTAR satellites spanning a period of 10 years since the discovery of the object.

1

Email : [email protected]

THE SIZE AND EXPANSION RATE OF THE MULTI-WAVELENGTH NEBULAE OF THE CRAB PULSAR Sally El-Sayeda,1, Abdullah Aaliyaa, Alaa Ibrahima a

Zewail City of Science and Technology, Physics of the Earth and Universe, Giza, Egypt

The Crab Nebula (M1) is the best observed and most recognized supernova remnant. The young pulsar at its center spins at a spin-period of 33 milliseconds and energizes the nebula to radiate from radio to gamma rays. Using archival observations during ~ 1950 - 2000, we study the multiwavelength nebula and calculate its average angular size in the radio, optical and x-ray wavelength, which are found to be 5.0265, 4.461 and 1.3965 arcmin, respectively, corresponding to a linear size of 83.77, 74.345 and 23.27 pc, respectively. We estimate the expansion rate of the radio, optical and x-ray nebulae to be 71961.7 km/s, 70303.45 km/s and 17494.88 km/s respectively. We discuss and compare our results with earlier work and confront them to current models of neutron stars and supernovae remnants.

1

Email: [email protected]

THE MUSE ATLAS OF DISKS (MAD) Santiago Erroz-Ferrer *1, Marcella C. Carollo*, Mark den Brok*, Martina Fagioli*, Masato Onodera,* † Sandro Tacchella*, Raffaella A. Marino* *Department of Physics, Institute for Astronomy, ETH Zurich, CH-8093 Zurich, Switzerland † Subaru Telescope, National Astronomical Observatory of Japan, HI 96720 Hilo, USA I will present the MUSE Atlas of Disks (MAD, Carollo et al. in prep) GTO survey. MAD observes a large representative sample of nearby ‘star-forming Main Sequence’ galaxies with the MUSE instrument on VLT at greater spatial and spectral resolution than any other previous 2D spectroscopic survey on these systems. Based on known structural and colour properties of these 108-1011 M¤ galaxies from HST imaging, MUSE provides with stellar and gaseous maps at very local scales (~100 pc), enabling detailed analysis of the gas properties, stellar and gas kinematics and stellar populations. I will present the first results of these diagnostics from the 25 galaxies observed so far. In Fig. 1, I show some of the multiple properties that can be derived with the full spectra of MUSE for one representative barred galaxy: NGC 289. Note the great spatial resolution achieved with our great signal-to-noise data. For example, the BPT diagrams can be now analysed at very small scales, contrary to the single point per galaxy that were produced in the past decade. These key diagnostics will enable us to understand how disk galaxies grow in size and mass with cosmic time, as well as the star-formation histories of the different galaxy substructural components such as bars, bulges, pseudo-bulges, star forming rings, HII regions, AGNs and inner disks.  

Figure 1. Results from the analysis of the MUSE data cubes for the spiral galaxy NGC 289. a) RGB image created using narrowband images centred on Hα (red), OIII (blue) and SII (green); b) Stellar mass surface density; c) and d) Gas and stellar velocity maps respectively; e) Map of the dust extinction. f) SFR map derived from the dust-corrected Hα flux. g) NII-BPT diagram at very local scales, where the purple dots are those bins in the star-forming region, blue are the bins in the composite region and yellow those in the AGN/shocks region. h) 2D map of the galaxy, colour-coded by the position of the region in the NII-BPT diagram as in g). 1

Email : [email protected]

Long Period Variable Stars And A New Approach To IC 1613 Star Formation History Seyed Azim Hashemi∗†1 , Atefeh Javadi† , Jacco Th. van Loon †

School of Astronomy, Institute for Research in Fundamental Sciences (IPM), Tehran, 19395-5531, Iran ∗ Department of Physics, Sharif University of Technology, Tehran, Iran  Lennard-Jones Laboratories, Keele University, ST5 5BG, UK

IC 1613 is a Local Group dwarf irregular galaxy that is located at distance of 750 kpc, a gas rich and isolated dwarf galaxy that has a low foreground extinction. These features together with enough data from various surveys(e.g. [2-3]) make us interested to study this galaxy with more detail. In this paper we present star formation history of IC 1613 using Long Period Variable stars (LPVs); a new and simple method that works well for nearby galaxies that their stellar population are resolved [1]. LPVs represent the very final stages of evolution of low- and intermediate-mass stars, and are very luminous and cool so that emit maximum brightness in near-IR bands. Since these stars have reached their maximum brightness at near infrared wavelengths, their luminosity is directly related to birth mass. Therefore by employing the theoretical models we construct the birth mass function and derive star formation history. In this paper, we use the data of Japanese-South African IRSF telescope which permits simultaneous imaging in the J,H and Ks bands and covers a field view of about 240 arcmin square [2]. Our analysis shows that the IC 1613 has had a constant star formation rate of 0.002 M /yr from 4.4 Gyr ago until 250 Myr ago, without any dominant star formation episode in this time. Furthermore this result approves that IC1613 hasnt had an important external or internal interaction in this time interval. References 1. Javadi, A., van Loon, J. T.,&. Mirtorabi, M. T., MNRAS, 414, 3394 (2011). 2. Menzies, J. W., Whitelock, P. A., &.Feast, M. W., MNRAS, 452, 910 (2015). 3. Sibbons, L. F., Ryan, S. G., Irwin, M., Napiwotzki, R., A&A, 573, A84 (2015).

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Email: [email protected]

Quantum Corrections to Entropy of Infra-Red Modified Horava Gravity Shabana Nisar*1, Syeda Shumail* *

COMSATS Institute for Information Technology, Lahore

Ever since the observation of Bekenstien [1, 2] that not only blackhole mechanics can be given the form of the laws of thermodynamics, with area of horizon playing the role of entropy, the surface gravity of temperature and the mass of the black hole as energy, the study of blackhole thermodynamics has been a very active area of research due to fundamental problems posed by such a connection. Hawking’s discovery that black holes actually radiate via thermal spectrum [3] gives credence to the idea that the connection between geometry and thermodynamical quantities is not incidental, rather reveals the underlying deep quantum structure of spacetime as the entropy associated with a single classical solution must have a microscopic origin in more fundamental degrees of freedom. In this paper, we study quantum corrections to the entropy of certain black hole solutions in Horava’s gravity which is a promising proposal for describing the ultra-violet behavior of General Relativity. It is found that unlike in classical GR, the entropy formula is drastically changed through quantum corrections in the Horava’s gravity by terms that are proportional to inverse of the horizon area. References 1. J. D. Bekenstein, Phys. Rev. D 7, 2333 (1973) . 2. J. M. Bardeen, B. Carter and S. W. Hawking, Commun. Math. Phys. 31, 161 (1973). 3. S. W. Hawking, Commun. Math. Phys. 43, 199 (1975) Erratum: [Commun. Math. Phys. 46, 206 (1976)] .

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[email protected]

ESTIMATION OF CORONAL SOLAR ROTATION USING 171 Å EXTREME UV IMAGES FROM SOHO Shivam Raval*1 and Hari Om Vats† * †

Indian Institute of Technology, Kharagpur, India Physical Research Laboratory, Ahmedabad, India

Rotation of the Sun is traditionally estimated by observing the motion of certain features on the solar surface e.g. sunspots [1], plages [2], filaments [3] etc. Recent advances have allowed us to precisely monitor the rotation of the sun using the means of spectroscopy [4] and flux modulation approach [5]. In the present work, we analyze the 171A extreme UV solar images from the SOHO Extreme ultraviolet Imaging Telescope (EIT) for the period of 20 years (January 1997 to August 2016) using the flux modulation approach to estimate the Sidereal Rotation Period of the Corona and analyze its present variation as a function of solar latitude for the estimation. This involves the techniques of Digital Image Processing to precisely observe the variation of average intensity in a small width at each latitude throughout the year. We perform time series analysis and observe that the periodic nature of auto-correlation plot of the intensities reveals the rotation period at a given latitude. We find the evidence of some important features such as the Differential Rotation as a function of latitude and the North-South Asymmetry in the Rotation Period of the Sun. We also substantiate that the variation of solar rotation rate with latitude has to be of a cubic form to incorporate the asymmetric effects in the Differential Rotation. References 1. 2. 3. 4.

L. Zhang, K. Mursula, and I. Usoskin, Astronomy & Astrophysics 575, 2 (2015) D. L. Glackin, Solar Physics 36, 51 (1974) J. Singh and T. P. Prabhu, Solar Physics 97, 203 (1985) Y. Takeda, O.Ohshima, E. Kambe, H. Toda, H. Koyano, B. Sato, Y. Nakamura, N. Narita, and T. Sekii, Publications of the Astronomical Society of Japan 67, 10 (2015) 5. Satish Chandra and Hari Om Vats, Monthly Notices of the Royal Astronomical Society 414, 3158 (2011)

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Email : [email protected]

STUDY OF UV STELLAR POPULATIONS IN M67 Sindhu N∗†1 , Annapurni Subramaniam† , C Anu Radha∗ ∗

Department of Physics, School of Advanced Sciences, VIT University, Vellore - 632014 † Indian Institute of Astrophysics, Bangalore - 560034

We investigate the old open cluster M67 using ultraviolet photometric data of GALEX in both FUV and NUV bands. Old open clusters are ideal laboratories to study star formation and stellar evolution since they consist of both single and binary evolved populations. M67 has a well-defined main sequence and red giant branch; is well studied in the optical region. This cluster has an evolved stellar population such as subgiant branch, white dwarfs, and exotic stars such as blue stragglers and yellow stragglers. 38% of the cluster stars are in binary systems (Montgomery et al. 1993). The cluster has 24 known blue stragglers(BSS), of those 17 are detected in the FUV band and 12 BSS in NUV band. We present the UV colour-magnitude diagram of the cluster, which is a guidance tool to identify the hot stellar population of the cluster; as shown in Fig 1 & Fig 2, the stellar populations are identified, and we plan to study them in detail. The spectral energy distribution(SED) of the blue stragglers and other hot stellar populations which are bright in the UV colour magnitude diagram are constructed in order to estimate their effective temperature and identify binary systems. Fig 3. shows the SED of a blue straggler WOCS 4003, the effective temperature is estimated to be 6750K, and is comparable to previous studies. The SED fit suggests an FUV excess indicating a possible white dwarf companion. 14 Blue stragglers

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Figure 1: NUV colour magni- Figure 2: FUV colour magni- Figure 3: SED of a blue stragtude diagram of M67 tude diagram of M67 gler, WOCS 4003 in M67 References 1. 2. 3. 4.

K. A. Montogomery, L. A. Marschall, and K. A. Janes, Astron. J 106, 181 (1993). T. Belloni, F. Verbunt, and R.D. Mathieu, Astron. Astrophys. 339, 431 (1998). L. Deng et al., Astrophys.J. 524, 824 (1999). M. van den Berg et al., Astron. Astrophys. 418, 509 (2004).

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Email: [email protected]

UV STELLAR POPULATION IN GLOBULAR CLUSTER M5: HORIZONTAL BRANCH MORPHOLOGY AND BLUE STRAGGLER STARS Snehalata Sahu*1, Annapurni Subramaniam* *

Indian Institute of Astrophysics, Koramangala II Block, Bangalore-560034, India

M5 is a Globular Cluster with a bimodal horizontal branch (HB) and a rich number of exotic stellar population such as Blue Straggler Stars (BSS). A proper understanding of these population using UV color magnitude diagrams (CMD) along with the stellar evolutionary model is still lacking. We present the UV population study of M5 using GALEX archive data. We have performed crowded field photometry on the GALEX images and estimated the FUV and NUV magnitudes of the stars in the cluster field. We have generated isochrones for the GALEX filter system using the Flexible Stellar Population Synthesis (FSPS) model [1], including HB as well as BSS. By comparing the UV CMD and the isochrones, we have identified various features and evolutionary phases in the CMD. We have also combined the GALEX data with HST-ACS [2] as well as ground based observations [3] of M5. Their comparison shows very interesting results in the morphology of HB and BSS. We have shown one such comparison with ground data, in the figure.

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Figure 1. Crossmatched GALEX data with ground based observations showing just the HB morphology in the (a) V vs (B-V) CMD, (b) NUV vs (NUV-V) CMD and (c) (NUV-V) vs (B-V) plots. We notice that the HB is no longer horizontal in the UV CMD. The HB stretches to a relatively large magnitude range in the NUV CMD (figure 1(b)). We also notice a deviation of the observed sequence from the model sequence towards the brighter part of the Blue HB. In the NUV CMD, the Blue HB is brighter than the red HB, as expected. We notice a few stars which deviate from the bulk of the distribution as seen in figure 1(c). We also notice that some Blue HB stars in the optical CMD, cross over to the location of Red HB stars in the UV CMD and vice versa, which are marked in the figure. More details of the HB as well as the BSS population along with other interesting UV bright stars in this cluster will be presented. References 1. Conroy, Gunn, and White, ApJ 699, 486 (2009). 2. Sarajedini et al., AJ 133, 1658 (2007). 3. Viaux et al., Astron. Astrophys. 558, A12 (2013). 1

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Plasma diagnostics in the Earth’s foreshock, bow shock and magnetosphere and the impact of IMF cone angle on total pressure in these regions. Suleiman M Baraka ∗1 *Center for Astronomy and Space Science Al Aqsa University, P.O. Box 4051, Gaza, Palestine 1 Institut d´Astrophysique de Paris, 98 bis Blvd Arago, 75015, Paris, France A modified version of (Baraka,2016) PIC code is used to simulate the foreshock,bow shock and the magnetosheath kinetic physics. IMF cone angle, pressures and other plasma parameters were discussed in this study mainly in the dayside magnetosphere. In Fig1 (physical units are measured in ion inertial length (di = ωcpi ) the thermal behavior of electrons(in blue)[usually absent in MHD simulation] is shown. Ions in red depicts important rotation of ions at the foreshock region.Additionally, small portions of these ions and larger number of electrons are backstreaming with high speed . It is evidently that the electrons small masses are offset by their high thermal motion, therefore their impact on ions by radiation can’t be ignored.

Figure 1. Velocity spatial distribution of ion and electron taken at nose direction at 3000 ∆t both in day and night side of the magnetosphere. The thermal behavior of electrons can be clearly seen in this figure, especially at the day side portion of the magnetosphere

References 1. 2. 3. 4.

S. Baraka J. Astrophys. Astr. 37:14,(2016) F. Plaschke, H. Hietala, V. Angelopoulos et al., J. Geophys. Res 121, 4 (2016). N. Omidi, J.Berchem, D. Sibeck et al., J. Geophys. Res. 121,4,(2016) H. Karimabadi, V. Roytershten, H. Vu et al., Phys of plasma 21, 62308 (2014). 1

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THE LITHIUM PROBLEM: NEW INSIGHT IN THE BIG BANG NUCLEOSYNTHESIS (BBN) BEYOND THE STANDARD MODEL Tahani Makki *1 and Mounib F. El Eid* *

Department of physics, American University of Beirut, Lebanon

Big Bang nucleosynthesis (BBN) is the only reliable theory to understand the formation of light elements in the universe during the first three minutes. The observed abundances of light elements are in good agreement for all elements except Lithium (7Li). The situation concerning 7Li abundance become very complicated because of the big discrepancy between observations and obtained from halo stars and the predictions of BBN supported by WMAP satellite. It seems that BBN predictions are higher by a factor of 2.4-4.3 than the observed abundance from globular cluster stars and halo field stars [1]. This problem attracted several groups around the world for finding a possible solution beyond the standard model of cosmology and particle physics. Despite of many scenarios we will focus on the contribution of two of them: the first one is the effect of degenerate neutrinos (non-vanishing chemical potentials) and the second one is the effect of adding dark component (dark energy density and dark entropy) [2]. These two scenarios have big impact on freeze-out of neutrons and Deuterium bottleneck which are the most important stages of BBN. So, it is important to do analytical and numerical analysis of these two stages because they determine the final elements abundances. Adding degeneracy parameter will have positive effect in solving the problem if the neutrinos chemical potentials are different. Concerning the dark component, the main contribution comes from adding dark entropy. A kind of complication is that the depletion of Lithium to be close to its observed value will produce high deuterium abundance which is in conflict with recent Deuterium observations [3]. Therefore, it is still worth investigating this fundamental problem of cosmology References 1. R. H. Cyburt, B. D. Fields, and K. A. Olive, JCAP 0811,012, (2008). 2. A. Arbey and F. Mahmoudi, JHEP 1005,051 (2010). 3. R. Cooke et al., Ap. J. 781, 31 (2014).

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RADIO ACTIVITY IN BRIGHTEST GROUP GALAXIES FADE OUT AS THE HALO AGES Vajiheh Sabzali*1, Halime Miraghaei†, Habib Khosroshahi†, Pantea Davoudifar*, Mojtaba Raouf†, Erfan Nourbakhsh† *



Research Institute for Astronomy and Astrophysics of Maragha (RIAAM), Maragha, Iran School of Astronomy, Institute for Research in Fundamental Sciences, PO Box 19395-5531, Tehran, Iran

GMRT observations of a number of fossil galaxy groups, as archetypal old and relaxed/virialised galaxy groups show that despite their massive stellar contents, they are under luminous in radio, arguably indicating that the lack of recent galaxy major merger in fossil groups has affected. In this work, a sample of fossil galaxy groups selected according to the method that we have developed to assign halo age to galaxy groups based on their optical measurable parameters, using a multidimensional analysis of the evolution of halo mass in galaxy groups in cosmological simulations, has been observed with GMRT at 610MHz. Here, we present the result of radio observations and compare radio luminosity of fossil galaxy groups with a sample of normal galaxy groups.

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PPMXL PHOTOMETRIC STUDY OF TWO NEWLY DISCOVERED OPEN CLUSTER ( SAI 19 AND SAI 23 ) Wasayf F. Alotaibi*1 *

King Abdul Aziz University, Kingdom of Saudi Arabia -21442 Jeddah

In this research, we studied the characteristics of two newly discovered stellar agglomeration to confirm their classification as open star clusters. Their structural (core radius, limiting radius, etc) and the astrophysical parameters (reddening, distance and age) have been investigated. The infra red photometric data, star coordinates as well as the proper motion data (PPMXL catalogue) are extracted from VizieR web site for the studied clusters. The Point Source Catalogue (PSC) of the Two Micron all Sky Survey (2MASS) is the source for the used photometric data in J, H and K infra red filters [1]. The studied newly discovered clusters are SAI 19 and SAI 23. They are selected from the SAI open star clusters catalogue [2]. The two clusters were not studied before. The centers of the clusters were determined and the distribution of star number density as a function of the radius far away from the center is derived for each cluster. The core radius of the two clusters lies in the range 2-4 arcmin, while their limited radius is in the range 7-14 arcmin. The most significant and important step in our study is cluster membership determination; to decontaminate the field stars from the vicinity of the cluster. To carry out this task, we apply a kinematical method, which is based on the proper motion of the stars in the cluster and the data is available for our targets. It is more effective method than the statistical one. The Topcat software and PPMXL catalog were used to achieve this step. The cleaned Color Magnitude Diagrams (CMDs) for each cluster is used to determine the astrophysical parameters (reddening, distance and age) through their fitting with Padova isochrones. The clusters SAI 19, SAI 23 and have ages of 0.4 and 0.3, respectively. The luminosity and mass functions of the studied clusters, as well as the total masses have been determined. The slope values of Initial Mass Function (IMF) of these clusters are close to the value (-2.5) for the field stars as given by Salpeter [3] References

1. Skrutskie, M., Cutri, R., Stiening, R., Weinberg, M., Schneider, S., Carpenter, J., Beichman, C., Capps, R., Chester, T., Elias, J., et al. The Astronomical Journal, 131(2):1163 (2006). 2. Glushkova, E., Koposov, S., Zolotukhin, I. Y., Beletsky, Y. V., Vlasov, A., and Leonova, S. Astronomy letters, 36(2):75–85 (2010). 3. Salpeter, E. E. The Astrophysical Journal, 121:161 (1955).

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DYNAMICAL DISSOLUTION OF THE AGED GALACTIC OPEN CLUSTER BERKELEY 17 W. P. Chen1, Souradeep Bhattacharya2, Ishan Mishra3, Kaushar Vaidya2 1

Graduate Institute of Astronomy, National Central University, Taoyuan, Taiwan 2 Birla Institute of Technology and Science, Pilani, India 3 Indian Institute of Technology Guwahati, India

We present the analysis of the morphology of Berkeley 17, the oldest known open cluster (10 Gyr), using a probabilistic star counting of Pan-STARRS point sources, and confirm its core-tail shape, plus an antitail, previously detected with 2MASS data. The stellar population, as diagnosed by the color-magnitude diagram and theoretical isochrones, shows more massive than lower-mass members in the cluster core, whereas there is a paucity of massive members in both tails. This manifests mass segregation in this aged star cluster with the low-mass members being stripped away from the system. It has been claimed that Berkeley 17is associated with an excessive number of blue stragglers. Our analysis in comparison of the cluster with nearby reference fields indicates that about half of the blue stragglers may be field contaminations, and some may be confused with the rare blue horizontal-branch stars in this cluster.

Figure 1. The field-cleaned g versus g-y color-magnitude diagram and corresponding member mass function for the core of Berkeley 17 and for the two tidal tails.

SEARCH FOR HIBITABLE PLANETS ECLIPSING ULTRA-COOL STARS SPECULOOS: SEARCHING FOR EXO-EARTHS AMENABLE FOR DETAILED ATMOSPHERIC CHARACTERIZATION Yaseen Almleaky *1 and Michaël Gillon† *

King Abdul Aziz University, Jeddah, Kingdom of Saudi Arabia † University of Liege, Belgium

The first detailed atmospheric characterizations of exoplanets similar in size and temperature to Earth are eagerly awaited. Theoretically, transit techniques represent a possible path to this breakthrough. Still, the extreme size- and brightness-ratios between an exo-Earth and its stellar host make virtually impossible its atmospheric characterization with existing and next generation astronomical facilities... except if the planet transits a nearby "ultra-cool dwarf" star, i.e. a Jupiter-sized star at the extreme bottom of the main-sequence. Unfortunately, these mini-stars, despite being very frequent in the Galaxy, have been mostly unexplored for planets so far. In this context, we present here the SPECULOOS project, a new transit survey targeting the ~500 brightest southern ultra-cool dwarfs based on four dedicated 1m robotic telescopes to be installed this year at ESO Paranal Observatory, Chile. We describe the concept and status of SPECULOOS, some results of its prototype ongoing since 2011 in Chile, and our current efforts to extend the project to the Northern hemisphere

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MÖSSBAUER SPECTROSCOPY OF PYROXENE IN THE LIGHT-DARK STRUCTURE OF THE KAPOETA METEORITE: IMPLICATIONS FOR THERMAL HISTORY OF THE KAPOETA PARENT BODY Yassir A. Abdu*1 *

Department of Applied Physics and Astronomy, University of Sharjah, United Arab Emirates

Pyroxene is one of the most common minerals in stony meteorites and on the surface of terrestrial planets and the moon. The intracrystalline Fe2+-Mg exchange reaction between the M1 and M2 octahedral sites in pyroxenes records the latest thermal event of the host rock. Kapoeta belongs to a rare group of achondrite meteorites called howardites, which along with eucrites and diogenites, constitute the HED meteorites; these are believed to originate on the asteroid 4 Vesta. Recently, there has been a renewed interest in the HED meteorites due to NASA’s Dawn mission to Vesta. Kapoeta is characterized as a polymict breccia with a light-dark structure, and the rock is dominantly composed of pyroxene. Here, we study the distribution of Fe2+ between the M1 and M2 sites of pyroxene in the light and dark regions of the Kapoeta meteorite by Mössbauer spectroscopy and single-crystal X-ray diffraction (XRD), in an attempt to better understand the thermal history of the meteorite parent body. Transmission Mössbauer spectra of powdered samples were acquired at room temperature (RT) using a 57Co(Rh) point source. The spectrometer was calibrated with the RT spectrum of α-Fe. The Mössbauer spectra of the light and dark regions of Kapoeta are practically identical and are characteristic of orthopyroxene. The spectra were fit using a Voigt-based quadrupole-splitting distribution (QSD) analysis to a model having one generalized QSD site for Fe2+, with two Gaussian components that are assigned to Fe2+ at the M1 (QS ≈ 2.5 mm/s) and M2 ( QS ≈ 2.1 mm/s) sites of orthopyroxene. The Fe2+-Mg ordering state of orthopyroxene crystals determined by single-crystal XRD, and the calculated closure temperatures (~ 400 °C) indicate a slow cooling rate for these crystals. The slow cooling rate, along with the composition of the investigated orthopyroxene crystals, suggests that these crystals come from a diogentic region deep within the HED parent body. On the other hand, the Mössbauer results indicate a more disordered Fe2+-Mg distribution between M1 and M2 sites in orthopyroxene, suggesting a fast cooling rate. This could be due to a shock and reheating, followed by rapid cooling, of the regolith material on the surface of the HED parent body.

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CHARGED SPACE OBJECTS PERTURBATION IN LOW EARTH ORBIT USING ELECTROMAGNETIC FORCE AND TORQUE EVALUATION Yehia Abdel-Aziz *1 *

National Research Institute of Astronomy and Geophysics (NRIAG), 11421 Cairo, Egypt

Space objects (debris and operational satellites) experience small perturbation torques and forces from their interaction with the surrounded space environment. In low Earth orbit (LEO), objects have been shown to charge and experienced with Lorentz forces in case of total and differential chagrining. This charging results in electrostatic forces and torque being produced due to the interactions with the Earth electric and magnetic fields. This paper investigates the effects of electrostatics forces and torque on the orbital and rotational motion of space object (debris and satellites), in particularly with High Area –to -Mass ratio (HAMR). Numerical simulations show how these electromagnetic forces and torques couple to stronger perturbations on the orbital motion and strong enough to change the position of the object within hundreds of meters over one period revolution of the object for certain highly charged HAMR objects. The results confirm that such forces can be compared with the force of air drag and can be used for deorbiting the debris in case of HAMR and highly charge to mass ratio. References 1. Y. Abdel-Aziz, Adv Space Res, 40, 18 (2007). 2. Y. Abdel-Aziz, and M. Shoaib, (RAA) 14, 891(2014a). 3. Y. Abdel-Aziz, and M. Shoaib, International Journal of Aeronautical and Space Sciences (IJASS) 15, 82 (2014b). 4. Y. Abdel-Aziz, and M. Shoaib, RAA, 15, 127 (2015). 5. B. Streetman and MA. Peck, J. Guid Control Dynam, 30, 1677 (2007) 6. J. W. Gangestad et al., J. Guid Control Dynam 32, 146 (2009) 7. G. E. Pollock et al., J. Guid Control Dynam, 33, 1387 (2010). 8. G. E. Pollock et. al., Acta Astronaut, 68, 204(1122). 9. X. Huang et. al., Adv Space Res, 53, 518(2014).

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Development Status of Carbon Fiber Mirror Young-Soo Kim, Jeong Gyun Jang, Jihun Kim, Jakyoung Nah, Uk Won Nam *

Korea Astronomy and Space Science Institute, Daeduck-dero 776, Daejeon, South Korea

Carbon fiber is a futuristic material being used for airplanes by its characteristics of light-weight and high stiffness. It is twice stronger than iron, but five times lighter than iron and two third of the weight of Aluminum. Therefore it becomes more widely used for light-weighing purposes in the cars, bicycles, golf shafts, and many other appliances. Astronomy and space sectors also adopted the material for structures, panels, and tubes of satellites, rockets, telescopes, and instruments. There have been attempts that carbon fiber is to be developed as an optical mirror material, as it has an additional advantage of low thermal expansion. For a telescope mirror both in space and on ground, low thermal expansion glass or ceramic is used like Zerodur, Clearceram, or ULE. However, they are heavy and brittle which require stronger and heavier supporting structures and extremely careful handling. In contrast to that, carbon fiber is so strong that it is not breaked or chipped. Making mirrors light-weight is hugely benefitial as the supporting structures are lighter and costs of construction and launch to space are reduced dramatically. We are currently developing carbon fiber mirror, from forming the mirror shaped blank from prepregs. Figure 1 shows molds and a sample blank of the carbon fiber mirror after forming. Diameters of the molds are 230 mm and 250 mm, and their curvatures are the same 520 mm. Several shapes have been produced by varying the number of sheets, which result in various thickness from 1 mm to 6 mm.

Figure 1. Molds and a mirror blank formed by carbon fiber.

There are several more steps to make a complete mirror from the mirror blank, from nickel plating to final aluminum coating on the mirror surface. Several methods have also been tried to plate nickel on the mirror blank, such as electroless plating, reverse process of plating and fiber forming, and nickel bonding. When glass mirror is replaced to carbon fiber mirror, lighter space telescope can made with lower cost and larger ground telescopes can be produced easily. And also it will be widely used on protable devices where light-weighting is benefited. References 1. Yoder, Jr. P. R., 2006, Opto-Mechanical Systems Design, SPIE Press, Washington, pp. 110~111. 2. Martin, R. N. and Romeo, R. C., 2006, “CFRP composite optical telescope assembly for the 1m ULTRA project,” Proc. SPIE, Vol. 6273, p. 627311. 3. Andrews, J.R., Penado, F.E., Broome, S.T., Wilcox, C.C., Restaino, S.R., Martinez, T., Teare, S.W., and Santifago, F., 2006, “Characterization of the Lightweight Telescope Developed for the NPOI,” Proc. SPIE, Vol. 6267, p. 62673Q

MONITORING OF COMETS ACTIVITY AND COMPOSITION WITH THE TRAPPIST-NORTH TELESCOPE Youssef Moulane*1, Zouhair Benkhaldoun*, Jehin Emmanuel†, Cyrielle Opitom†, Michael Gillon†, and Ahmed Daassou* *

Oukaimeden Observatory, LPHEA, FSSM, Cadi Ayyad University, Morocco † Institute of Astrophysics and Geophysics, University of Liege, Belgium

TRAPPIST-North (TRAnsiting Planets and PlanetesImals Small Telescope), is a 60-cm robotic telescope that was installed in May 2016 at the Oukaimeden Observatory [1]. The project is led by the University of Lige (Belgium) and the Caddi Ayad University of Marrakech (Morocco). This telescope is a twins of TRAPPIST-South telescope which was installed in the ESO La Silla Observatory in 2010 [2]. The TRAPPIST telescope dedicated to the detection and characterization of planets orbiting stars other than our Sun (exoplanets) and the study of comets and other small bodies in our solar system [3]. About the last thematic, these telescopes have a very sensitive CCD camera with complete sets of cometary narrow band filters in order to measure the production rates of several gas species (OH, NH, CN, C3 and C2) and the dust [4]. With TRAPPIST-North we can now also observe comets would be invisible in the southern hemisphere. So, with these two telescopes, we can continuously the comets around their orbit. We present in this work our strategy to study the evolution of the activity, chemical composition, dust properties, and coma morphology of several comets per year and of different origins (New comets and Jupiter Family comets) over a wide range of heliocentric distances, and on both sides of perihelion. We will measure the production rates of each daughter molecules using a Haser model [5], in addition to the Af parameter estimate the dust production in the coma. We will compute the production rates of the daughter molecules to OH and the gas/dust ratio, all quantities allowing classify comets [6] in order to better understand the link between the chemical composition of comets and their origins. In addition to the study of bright comets, a photometric monitoring of fainter comets is performed with broad band filters in order to measure the evolution of their dust production and detect outbursts that are caused by a non-uniformly active nucleus, with active areas. We will also observe periodic comets on consecutive returns and study the evolution of their secular light curve [7]. References 1. 2. 3. 4. 5. 6. 7.

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http://moss-observatory.org/ E. Jehin et al., The Messenger145, 2 (2011). http://www.orca.ulg.ac.be/TRAPPIST/Trappist T.L. Farnham et al., Icarus 147, 180 (2000). L. Haser, Bulletin de lAcadmie Royale de Belgique 43, 740 (1957). M. F. AHearn et al., The Astronomical Journal 89, 579 (1984). N. H. Samarasinhaa and S. M. Larson, Icarus 239, 168 (2014).

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A Real-Time Data Reduction Pipeline for Time-Series Stellar Photometry Zach Ioannou*1 & Milan Bogosavliević† *

Department of Physics, College of Science, Sultan Qaboos University, Muscat, Oman † Department of Physics, New York University Abu Dhabi, UAE † Astronomical Observatory Belgrade, Volgina 7, Belgrade, Serbia

We present a newly developed pipeline for time series photometric data. The main modules of the software are written in Python while the main user interface is through the widely popular and user friendly SAOImage DS9 package. The developed software requires minimum human supervision and can stream live photometric data via the internet using an asynchronous broadcasting library. A live-data photometric monitor can also be used as a collaboration tool between observers at distant observatories or for the real-time monitoring of the data collection process of a robotic telescope. The modular design of the software allows for easy adaptation of the pipeline to specific projects (transient source follow-ups, exoplanet searches etc).

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Email : [email protected]