Search Publications
On timing and spectral characteristics of the X-ray pulsar 4U 0115+63: Evolution of the pulsation period and the cyclotron line energy
Tsygankov, S. S.; Lutovinov, A. A.; Boldin, P. A.
An overview of the results of observations for the transient X-ray pulsar 4U 0115+63, amember of a binary system with a Be star, since its discovery to the present day (∼40 years) based on data from more than dozen observatories and instruments is presented. An overall light curve and the history of change in the spin frequency of the neutron star…
Galactic kinematics from a sample of young massive stars
Bobylev, V. V.; Bajkova, A. T.
Based on published sources, we have created a kinematic database on 220 massive (> 10 M ⊙) young Galactic star systems located within ≤3 kpc of the Sun. Out of them, ≈100 objects are spectroscopic binary and multiple star systems whose components are massive OB stars; the remaining objects are massive Hipparcos B stars with parallax …
Estimation of the solar galactocentric distance and galactic rotation velocity from near-solar-circle objects
Bobylev, V. V.
We have tested the method of determining the solar Galactocentric distance R 0 and Galactic rotation velocity V 0 modified by Sofue et al. using near-solar-circle objects. The motion of objects relative to the local standard of rest has been properly taken into account. We show that when such young objects as star-forming reg…
Identification of four X-ray sources from the INTEGRAL and Swift catalogs
Tsygankov, S. S.; Lutovinov, A. A.; Eselevich, M. V. +5 more
Four hard X-ray sources from the INTEGRAL and Swift catalogs have been identified. X-ray and optical spectra have been obtained for each of the objects being studied by using data from the INTEGRAL, Swift, ROSAT, and Chandra X-ray observatories as well as observations with the RTT-150 and AZT-33IK optical telescopes. Two sources (SWIFT J1553.6+260…
Second outburst of the black hole candidate MAXI J1836-194 from SWIFT and INTEGRAL observations
Sunyaev, R. A.; Grebenev, S. A.; Prosvetov, A. V.
Details of the observations of a new (second) outburst of the X-ray transientMAXI J1836-194 discovered late in August 2011, a suspected black hole in a low-mass binary system, with the instruments of the SWIFT and INTEGRAL orbiting observatories are presented. The outburst was weaker than the first one; the source had a power-law spectrum in a wid…
Galactic orbits of Hipparcos stars: Classification of stars
Bajkova, A. T.; Gontcharov, G. A.
The Galactic orbits of 27 440 stars of all classes with accurate coordinates and parallaxes of more than 3 mas from the Hipparcos catalogue, proper motions from the Tycho-2 catalogue, and radial velocities from the Pulkovo Compilation of Radial Velocities (PCRV) are analyzed. The sample obtained is much more representative than the Geneva-Copenhag…
Old stellar subsystems in dwarf galaxies
Tikhonov, N. A.
Based on archival Hubble Space Telescope ACS/WFC images, we have performed stellar photometry for eight dwarf galaxies of different types (Irr, S0, E) with a populated horizontal branch on their Hertzsprung-Russell diagrams. We have identified probable RR Lyr stars in these galaxies and constructed the distribution of their number density along th…
Outburst of the unknown source IGR J18175-2419 detected by the INTEGRAL observatory: Yet another fast X-ray transient?
Grebenev, S. A.
The discovery of a new X-ray source, IGR J18175-2419, that flared up for a short (∼1 h) time on September 26, 2012, by the INTEGRAL observatory is reported. The results of the source's localization and the spectral/timing analysis of its X-ray emission are presented. The source may turn out to be yet another representative of the population of fas…
Stellar subsystems of the young tidal dwarf galaxy Ho IX
Tikhonov, N. A.; Galazutdinova, O. A.
Based on archival Hubble Space Telescope ACS/WFC images, we have performed stellar photometry for the young tidal dwarf galaxy Ho IX. We have determined that star formation in Ho IX began 110 Myr ago and ended 20 Myr ago. We have identified 20 young star clusters in the galaxy with ages from 25 to 100 Myr. For the main star-forming region of Ho IX…