Search Publications
Ultra-luminous X-ray sources as supercritical accretion disks: Spectral energy distributions
Vinokurov, A.; Atapin, K.; Fabrika, S.
We describe a model of spectral energy distribution in supercritical accretion disks (SCAD) based on the conception by Shakura and Sunyaev. We apply this model to five ultra-luminous X-ray sources (ULXs). In this approach, the disk becomes thick at distances to the center less than the spherization radius, and the temperature dependence is T ∝ r
Distances to dwarf galaxies of the Canes Venatici I cloud
Makarova, L. N.; Makarov, D. I.; Uklein, R. I.
We determined the spatial structure of the scattered concentration of galaxies in the Canes Venatici constellation. We redefined the distances for 30 galaxies of this region using the deep images from the Hubble Space Telescope archive with the WFPC2 and ACS cameras.We carried out a high-precision stellar photometry of the resolved stars in these …
Stars with discrepant v sin i as derived from the Ca II λ3933 Å and Mg II λ4481 Å lines. IV. HD8837—a shell star, HD47964 and HD183986—new binaries
Stateva, I.; Semenko, E.; Kudryavtsev, D. +4 more
Axial rotation of a star plays an important role in its evolution, physical conditions in its atmosphere, and appearance of its spectrum. We have analyzed CCD spectra of three stars for which their projected rotational velocity remarkably differs when derived from the Ca II λ 3933 Å and MgII λ 4481 Å lines. We derived effective temperatures and su…
Does the contribution of infrared and submillimeter sources reveal itself at low harmonics of the CMB?
Verkhodanov, O. V.; Naiden, Ya. V.
We have computed and studied the mosaic correlation maps of the ILC WMAP microwave background data with the positions of infrared and submillimeter sources. Using the histograms of the signal values in pixels and angular power spectra, we studied the statistical properties of these maps. We discovered similar behavior of a number of harmonics in t…
On two low harmonics of CMB correlation maps
Verkhodanov, O. V.; Naiden, Ya. V.; Keshelava, T. V.
We have analyzed two powerful correlation harmonics (ℓ = 3and ℓ = 6) found in the correlation of the ILC WMAP signal with the submillimeter and infrared range data from the FSC IRAS and Planck catalogs. The mode phases of thesemultipoles were computed. In the spots we have found in the harmonics, the source counts were made from the NVSS, FIRST, F…
Short gamma-ray bursts in the SPI-ACS INTEGRAL experiment
Minaev, P. Yu.; Pozanenko, A. S.; Loznikov, V. M.
We analyze short-duration gamma-ray bursts (T90<2 s) recorded in the SPI-ACS experiment of the INTEGRAL observatory. We found an extended emission in the averaged light curve of both short-duration gamma-ray bursts and unidentified short-duration events. We show that the fraction of short-duration gamma-ray bursts among all the gamma…
Orbits of new Hipparcos binaries: III
Balega, Yu. Yu.; Balega, I. I.; Malogolovets, E. V.
We present apparent orbits and fundamental parameters of three pairs of early M-type dwarfs. The orbital elements are determined from speckle interferometric observations at the 6-m BTA telescope of the Special Astrophysical Observatory. The orbits of two pairs, HIP39402 and HIP 104565 are built for the first time. The orbit of HIP106972 is revise…
Kinematics of high proper motion stars determined from high resolution spectra in ground-based ultraviolet
Klochkova, V. G.; Tavolganskaya, N. S.
Radial velocities for 15 stars with high proper motions were measured as a result of spectral observations, conducted with the NES echelle spectrograph of the 6-m BTA telescope in the wavelength range of 3550–5100 Å with a spectral resolution of R=60000. The standard deviation of the measured velocity does not exceed σ ≤ 0.9 km/s for the stars wit…
Parameters of the visually close binary system Hip11253 (HD14874)
Al-Wardat, M. A.; Widyan, H.
The physical and geometrical parameters of the individual components of the binary system Hip11253 (HD14874) are estimated. We used the method described in previous papers, which consists in getting the best fit between the entire observational spectral energy distribution of the system and the synthetic ones, created from model atmospheres. The p…
Synthetic photometry of speckle interferometric binaries
Al-Wardat, M. A.
The synthetic magnitudes and color indices of 46 speckle interferometric stars have been computed depending on their observational spectral energy distributions. The Strömgren vby and Tycho BV passbands have been used to calculate magnitudes of the systems. These data when combined with the magnitude differences of the sub-components from speckle …