Search Publications
Investigation of the Kinematics of Stars from the Gaia Data Release 2 with Radial Velocities Catalogue Using Scalar and Vector Spherical Harmonics
Tsvetkov, A. S.; Amosov, F. A.; Petrov, S. D. +1 more
This paper is a continuation of our work. The proper motions and radial velocities of stars from the Gaia DR2 with RV catalogue have been decomposed. We have confirmed that the Ogorodnikov-Milne model is consistent with the observational data and found the kinematic components that are not described by this model. The beyond-the-model harmonics ha…
Spectroscopy of B and Be Stars in the Young Open Star Cluster NGC 581 (M 103)
Tarasov, A. E.
Based on moderate-resolution spectra in the range 4200-5200 Å, we have studied B and Be stars in the young open star cluster NGC 581. The temperatures of the program stars have been derived by the differential method with the choice of simple spectroscopic parameters for a number of lines and their comparison with the analogous parameters of a lar…
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…