Search Publications
Dust in the disk winds from young stars as a source of the circumstellar extinction
Grinin, V. P.; Tambovtseva, L. V.
We consider the problem of dust grain survival in the disk winds from T Tauri and Herbig Ae stars. For our analysis, we have chosen a disk wind model in which the gas component of the wind is heated through ambipolar diffusion to a temperature of ∼104 K. We show that the heating of dust grains through their collisions with gas atoms is …
Optical identifications of five INTEGRAL hard X-ray sources in the Galactic plane
Bikmaev, I. F.; Sunyaev, R. A.; Sakhibullin, N. A. +4 more
The results of optical identifications of five hard X-ray sources in the Galactic plane from the INTEGRAL all-sky survey are presented. The X-ray data on one source (IGR J20216+4359) are published for the first time. The optical observations were performed with the 1.5-m RTT-150 telescope (Turkish National Observatory, Antalya, Turkey) and the 6-m…
Red giant clump in the Tycho-2 catalogue
Gontcharov, G. A.
The Tycho-2 proper motions and Tycho-2 and 2MASS photometry are used to select 97348 red giant clump (RGC) stars. The interstellar extinction and photometric distance are calculated for each of the stars. The selected stars are shown to form a selection-unbiased sample of RGC stars within about 350 pc of the Sun with the addition of more distant s…
New active galactic nuclei among the INTEGRAL and SWIFT X-ray sources
Bikmaev, I. F.; Sunyaev, R. A.; Sazonov, S. Yu. +4 more
We present the results of our optical identifications of a set of X-ray sources from the INTEGRAL and SWIFT all-sky surveys. The optical data have been obtained with the 1.5-m Russian-Turkish Telescope (RTT-150). Nine X-ray sources have been identified with active galactic nuclei (AGNs). Two of them are located in the nearby spiral galaxies MCG-01…
Dynamical study of wide pairs of stars based on data from the WDS catalog
Kiselev, A. A.; Kiyaeva, O. V.; Izmailov, I. S.
Using the method of apparent motion parameters, we have studied the relative motion of the components in 561 pairs of wide ( ρ > 2″) and relatively nearby (Hipparcos parallaxes > 0.01″) visual double stars based on data from the WDS catalog. The minimum masses of the double stars have been calculated at given parallaxes. We have identified 3…
Black hole at the center of the globular cluster M15: Estimation of the mass and specific angular momentum
Kiselev, A. A.; Shakht, N. A.; Gnedin, Yu. N. +3 more
Using the technique of determining the sum of the masses of double stars, we have estimated the mass of the central object in the globular cluster M15. The radial velocities of stars at distances up to 1″ from the cluster center have been used. The parameters of circular orbits and the space velocities of 11 selected field stars relative to the cl…
XTE J1901+014—the first low-mass Fast X-ray transient?
Lutovinov, A. A.; Karasev, D. I.; Burenin, R. A.
We continue to study the fast X-ray transient XTE J1901+014 discovered in 2002 by the RXTE observatory, whose nature has not yet been established. Based on the XMM-Newton observations of the source in 2006, we have obtained its energy spectrum, light curves, and power spectrum in the energy range 0.5 10 keV, which are in good agreement with our re…
Unusual stripes in emission and absorption in solar radio bursts: Ropes of fibers in the meter wave band
Chernov, G. P.
Based on data from the spectrographs of IZMIRAN and Tremsdorf station (Astronomical Institute, Potsdam), we analyze the ropes of narrow-band fibers in the spectra of solar radio bursts in the meter wave band by invoking events of satellite data (SOHO/LASCO, EIT, MDI) for the analysis. We consider in detail basic properties of the ropes in four eve…
OB stars in the Tycho-2 and 2MASS catalogues
Gontcharov, G. A.
The Tycho-2 proper motions and five-band Tycho-2 and 2MASS photometry for approximately 2.5 million common stars have been used to select OB stars and to determine the extinction and photometric distance for each of them. We have selected 37 485 stars and calculated their reddenings based on their positions in the two-color V T - H, J-…
Inaccuracies in the spectral classification of stars from the Tycho-2 Spectral Type Catalogue
Tsvetkov, A. S.; Popov, A. V.; Smirnov, A. A.
We compare the spectroscopic and trigonometric parallaxes of common stars from the Tycho-2 Spectral Type and Hipparcos Catalogues. This comparison has revealed that the distance estimations for the overwhelming majority of stars by both methods yield very similar results. However, there is a small fraction of stars for which the distance estimates…