Search Publications
The Orbits of 451 Wide Visual Double Stars
Izmailov, I. S.
Based on positional observations, we have determined the orbits of 130 visual double stars for the first time and improved the orbits of 321 stars. The histogram of eccentricities for all of the derived orbits corresponds to the relation f = 2e. The period distribution has two pronounced maxima at P ≈ 200 and ≈550 yr. The ephemeris relative positi…
Even-to-Odd Barium Isotope Ratio in Selected Galactic Halo Stars
Belyaev, A. K.; Mashonkina, L. I.
We have improved the Ba II model atom by taking into account the excitation of transitions through collisions with hydrogen atoms with the rate coefficients from the quantum-mechanical calculations of Belyaev and Yakovleva (2018). Using high-resolution spectra and Ba II line modeling when abandoning the assumption of LTE, we have determined the fr…
Kinematic Properties of Open Star Clusters with Data from the Gaia DR2 Catalogue
Bobylev, V. V.; Bajkova, A. T.
We consider open star clusters (OSCs) with the proper motions, parallaxes, and line-of-sight velocities calculated by various authors from Gaia DR2 data. The distance scale factor has been found by analyzing the separate solutions of the basic kinematic equations to be p =1.00 ± 0.04. It shows that the distances calculated using the parallaxes fro…
Kinematics of the Galaxy from a Sample of Young Open Star Clusters with Data from the Gaia DR2 Catalogue
Bobylev, V. V.; Bajkova, A. T.
We have selected a sample of 326 young (log t < 8) open star clusters with the proper motions and distances calculated by various authors from Gaia DR2 data. The mean values of their line-of-sight velocities have also been taken from various publications. As a result of our kinematic analysis, we have found the following parameters of the angul…
Parameters of the Link between the Optical and Radio Frames from Gaia DR2 Data and VLBI Measurements
Bobylev, V. V.
Based on published data, we have assembled a sample of 88 radio stars for which there are both trigonometric parallax and proper motion measurements in the Gaia DR2 catalogue and VLBI measurements. A new estimate of the systematic offset between the optical and radio frames has been obtained by analyzing the Gaia-VLBI trigonometric parallax differ…
Galactic Rotation Based on OB Stars from the Gaia DR2 Catalogue
Bobylev, V. V.; Bajkova, A. T.
We have studied a sample containing 6000 OB stars with proper motions and trigonometric parallaxes from the Gaia DR2 catalogue. The following parameters of the angular velocity of Galactic rotation have been found: Ω0 = 29.70 ± 0.11 km s-1 kpc-1, Ω'0 = -4.035 ± 0.031 km s-1 kpc-2, a…
New Gamma-Ray Bursts Found in the Archival Data from the IBIS/ISGRI Telescope of the INTEGRAL Observatory
Minaev, P. Yu.; Pozanenko, A. S.; Grebenev, S. A. +1 more
A systematic search for cosmic gamma-ray bursts (GRBs) and other short hard X-ray events in the archival data from the IBIS/ISGRI telescope of the INTEGRAL observatory over 2003-2018 has been carried out. Seven previously unknown GRBs have been recorded in the telescope field of view; all of them have been localized with an accuracy ≤2 arcmin. The…
Spectral Properties of Heavily Obscured Seyfert Galaxies from the INTEGRAL All-Sky Survey
Sazonov, S. Yu.; Krivonos, R. A.; Semena, A. N.
We have investigated the X-ray spectral properties of the ten heavily obscured nearby ( z < 0.1) active galactic nuclei (AGNs) IGR J00256+6821, NGC 1194, CGCG 420-015, IGR J09253+6929, NGC 3281, NGC 4939, IGR J14175-4641, NGC 5643, NGC 5728, and ESO 137-G034 from the catalogue of hard X-ray sources detected during the INTEGRAL seven-year all-sk…
On the Properties of the Galactic Dust Layer within 700 pc of the Sun
Gontcharov, G. A.
We compare the spatial stellar color variations with our three-dimensional analytical model of the spatial dust distribution to refine the properties of the dust layer in Galactic solar neighborhoods. We use a complete sample of 93 992 clump giants with a small admixture of branch giants from the Gaia DR2 catalogue in a spatial cylinder with a rad…
Kinematic Parameters of the Stellar Velocity Field within 3 kpc of the Sun Based on the Gaia Data Release 2 with Radial Velocities Catalogue
Tsvetkov, A. S.; Amosov, F. A.
The paper is devoted to determining the parameters of the three-dimensional Ogorodnikov—Milne kinematic model based on the Gaia DR2 star catalogue (the subset of seven million stars containing radial velocities). The behavior of the parameters as a function of the distance to stars is studied. The parameters derived from the stellar proper motions…