Search Publications
Detection of the Long Period Variable Stars of And II Dwarf Satellite galaxy
van Loon, J. Th.; McDonald, I.; Javadi, A. +5 more
We conducted an extensive study of the spheroidal dwarf satellite galaxies around the Andromeda galaxy to produce an extensive catalog of LPV stars. The optical monitoring project consists of 55 dwarf galaxies and four globular clusters that are members of the Local Group. We have made observations of these galaxies using the WFC mounted on the 2.…
Unraveling the Origins and Development of the Galactic Disk through Metal-Poor Stars
Mardini, Mohammad K.; Abushattal, Ahmad A.; Rah, Maria +2 more
The Milky Way is a spiral galaxy comprising three main components: the Bulge, the Disk, and the Halo. Of particular interest is the Galactic disk, which holds a significant portion of the baryonic matter angular momentum and harbors at least two primary stellar populations: the thin and thick disks. Understanding the formation and evolution of the…
The Pleiades flare stars in the Gaia era
Ghazaryan, S.; Hambaryan, V.; Hambardzumyan, L. +3 more
We study the six-dimensional arrangement of flare stars in the Pleiades cluster region using the third release of the Gaia–mission (Gaia DR3) and we provide preliminary, a new, original view of the spatial configuration of the flare "star-members" of the cluster.
Kinematic structure of the stellar population of the solar neighborhood by Gaia DR3
Vereshchagin, S. V.; Chupina, N. V.; Postnikova, E. S. +1 more
The data of modern catalogs allow us to consider in detail the issue of the spatial velocity distribution. The stars in the solar vicinity make it possible to avoid errors and draw detailed conclusions about their kinematics. For a corrected study, we took a sample of stars from the Gaia DR3 within 300 pc. This area contains a number of star clust…
TYC 1417-891-1 and TYC 1478-742-1: Eclipsing variable stars. The Gaia EDR3 and TESS photometric data.
Gigoyan, K. K.; Gigoyan, K. S.; Kostandyan, G. R.
Based on the TESS (Transiting Exoplanet Survey Satellite) phase dependent light curves, we confirm the eclipsing type variability nature for two G - type dwarfs: TYC 1417-891-1 and TYC 1478-742-1. Both objects show EA (Algol - type) light curves morphology. Orbital period for TYC 1417-891-1 is P ≈ 8.0 day and for TYC 1478-742-1, P ≈ 13.6 day. We p…
Observational evidence of instability phenomena related to open star clusters based on Gaia data
Kovaleva, D. A.
The vast amount of high-quality astrometric and photometric data from Gaia space mission opened new prospects in the investigation of the population of galactic star clusters. In particular, a number of observational evidence have emerged in relation to the phenomena of instability that previously were mainly predicted by dynamical simulations. Th…
Observations of Gaia Microlensing Events in Abastumani
Kvernadze, T.; Kvaratskhelia, O.; Kozlov, V.
Gaia is now one of the most successful and leading transient space mission. It discovers nearly 2000 objects annually from all over the sky, down to about 20 mag, covering all possible classes of transients from supernovae and cataclismic variables to rare phenomena like microlensing events or pair-instability supernovae. The long time baseline of…
Investigations of late-type giant stars from the First Byurakan Spectral Sky Survey
Gigoyan, K. K.; Gigoyan, K. S.; Kostandyan, G. R.
We study late-type giants found in the First Byurakan Survey (FBS) data base. The third Gaia data release (Gaia EDR3) photometric and astrometric data have been used to characterize our sample of 1 100 M-type giants and 130 C-type stars found at high latitudes. Phase dependent light-curves from large sky area variability data bases such as Catalin…
Search and identification of high-velocity stars by dynamical ejection and supernovae from multiple stars
Hambaryan, V.; Neuhaeuser, R.
The project, funded by Science Committee of RA (ARPI program), intended to search, detection, kinematic study and identification of the birth places of the high-velocity and isolated neutron stars that encountered in the past with a stellar groups (multiple stars, stellar clusters, associations, etc.) closer than 10 pc, i.e. to test the concept: a…
Study of the X-ray properties of radio sources, based on NVSS catalogue
Mickaelian, A. M.; Abrahamyan, H. V.; Paronyan, G. M. +4 more
An identification of radio sources from the NVSS list with ROSAT X-ray sources was made as well as also with optical objects from SDSS DR 16. We have tried to find the connection between the fluxes of different wave ranges, for different types of objects. We also have tried to find the relationship between the sizes and polarization angles of sour…