arXiv subjects
Publications and source records attributed to S. B. Popov.
We present here the computer model of the distribution of the luminosity, produced by old isolated neutron stars (OINSs) accreting from the interstellar medium (ISM). We show, that for different mean velocities of OINSs the distribution of the luminosity has a torus-like structure, with the maximum at $\approx 5 kpc$.
We present a WWW-version of the {\it Scenario Machine} - a computer code designed to calculate the evolution of close binary stellar systems. The Internet users can directly access to the code and calculate binary evolutionary tracks with parameters at the user's will. The program is running on the {\it Pentium} server of the Division of the Relativistic Astrophysics of the Sternberg Astronimical Institute (http://xray.sai.msu.su/ ). The results are presented both in the form of tables and graphic diagrams. The work is always in progress. More possibilities for Internet users are intended to become available in the near future.
We model the evolution of the selected types of X-ray sources (both with BHs and NSs) for the star formation burst at the Galactic center. For the currently assumed starburst age of 4-7 millions years, our results are consistent with the recent {\it GRANAT} X-ray observations of the Galactic center and predict a substantial number of X-ray binaries with black holes. In addition we made a very simple model of the spatial distribution of the X-ray sources, which is also consistent with the {\it GRANAT} observations. The results can be applied to other starformation regions.
X-ray binary population at the Galactic center is proposed here to form as a result of a starburst, which is synthesized by using the ``Scenario Machine'' code of binary star evolution. For the currently assumed starburst age of 4-7 millions years, our results are consistent with the recent {\it GRANAT} X-ray observations of the Galactic center and predict a substantial number of X-ray binaries with black holes.
The distribution of neutron stars (NS's) is determined by stationary solution of the Fokker-Planck equation. In this work using the observed period changes for four systems: Vela X-1, GX 301-2, Her X-1 and Cen X-3 we determined D, the 'diffusion coefficient',-parameter from the Fokker-Planck equation. Using strong dependence of D on the velocity for Vela X-1 and GX 301-2, systems accreting from a stellar wind, we determined the stellar wind velocity. For different assumptions for a turbulent velocity we obtained $V=(660-1440) km s ^{-1}$. It is in good agreement with the stellar wind velocity determined by other methods. We also determined the specific characteristic time scales for the 'diffusion processes' in X-ray pulsars. It is of order of 200 sec for wind-fed pulsars and 1000-10000 sec for the disk accreting systems.