Search Publications
Scandium Abundance in F-G-K Stars in a Wide Metallicity Range
Mashonkina, L. I.; Romanovskaya, A. M.
A new Sc II model atom has been constructed using up-to-date atomic data. To test it, we have carried out nonlocal thermodynamic equilibrium (non-LTE) calculations for three stars with reliably determined atmospheric parameters: the Sun, HD 61421 (Procyon), and HD 84937. Allowance for the departures from LTE leads to a decrease in the root-mean-sq…
Estimation of the Mass of the Very Massive Galaxy Cluster SRGe CL2305.2-2248 from Strong Lensing
Bikmaev, I. F.; Gilfanov, M. R.; Khamitov, I. M. +10 more
SRGe CL2305.2-2248 (SPT-CL J2305-2248, ACT-CL J2305.1-2248) is one of the most massive galaxy clusters at high redshifts ($z∼eq 0.76$) and is of great interest for cosmology. Deep images have been obtained at the Russian-Turkish 1.5-m telescope (RTT-150) for an optical identification of this cluster. In combination with the open Hubble Space Teles…
To the Globular Cluster Classification Problem. Calculating the Concentration of Stars for 26 Clusters
Nuritdinov, S. N.; Tatjibaev, I. U.; Rastorguev, A. S.
In view of the absence of a satisfactory solution to the globular cluster (GC) classification problem, we have searched for a physical parameter that admits of the GC classification and finding empirical dependences on observed physical characteristics. For this purpose, we have considered a model of the apparent density in GCs with three free par…
Influence of Collisions with Hydrogen on Titanium Abundance Determinations in Cool Stars
Sitnova, T. M.; Yakovleva, S. A.; Belyaev, A. K. +1 more
The possibility of solving the problem of a discrepancy in the non-LTE abundances from Ti I and Ti II lines in metal-poor stars is investigated by applying accurate data to take into account the collisions with hydrogen atoms. For this purpose, we have calculated for the first time the rate coefficients for bound-bound transitions in inelastic col…
Edge-on Galaxies in the Hubble Ultra Deep Field
Savchenko, S. S.; Reshetnikov, V. P.; Usachev, P. A.
We have produced a sample of 58 edge-on spiral galaxies at redshifts z 1 selected in the Hubble Ultra Deep Field. For all galaxies we have analyzed the 2D brightness distributions in the V 606 and i 775 filters and measured the radial ( h r ) and vertical ( h z ) exponential scale lengths of the bright…
Sizes of the stellar subsystems of galaxies and intracluster stars in the Virgo cluster.
Tikhonov, N. A.
Stellar photometry for three fields in the Virgo cluster of galaxies has been performed on the basis of archival Hubble Space Telescope ACS/WFC images. The densely populated red giant branches belonging to cluster galaxies are seen on the constructed Hertzsprung-Russell diagrams. The distances to eight galaxies in the Virgo cluster have been deter…
Rotation curve and mass distribution in the Galaxy from the velocities of objects at distances up to 200 kpc
Bobylev, V. V.; Bajkova, A. T.
Three three-component (bulge, disk, halo) model Galactic gravitational potentials differing by the expression for the dark matter halo are considered. The central (bulge) and disk components are described by the Miyamoto-Nagai expressions. The Allen-Santillán (I), Wilkinson-Evans (II), and Navarro-Frenk-White (III) models are used to describe the …
Stellar subsystems of the galaxy NGC 1313
Tikhonov, N. A.; Galazutdinova, O. A.
Based on archival Hubble Space Telescope (HST) ACS/WFC images, we have performed stellar photometry for eight fields of the spiral galaxy NGC 1313 and its satellite, the low-mass Sph/Irr galaxy AM0319-662. Stars of various ages have been identified on the constructed Hertzsprung-Russell diagrams: young supergiants, middle-aged stars, and old stars…
Spectroscopic study of the peculiar galaxy IC 883
Burenkov, A. N.; Karataeva, G. M.; Yakovleva, V. A. +3 more
We analyze new optical spectroscopic observations obtained at the 6-m telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences with the SCORPIO focal reducer (in the modes of a Fabry-Perot interferometer (FPI) and long-slit spectroscopy) and the Multi-Pupil Fiber Spectrograph for the galaxy IC 883. We have confirmed th…
M 101 group galaxies
Tikhonov, N. A.; Galazutdinova, O. A.; Lebedev, V. S.
Based on archival Hubble Space Telescope images, we have performed stellar photometry for the galaxy M 101 and other neighboring galaxies located at a small angular distance from M 101 and having radial velocities similar to that of M 101: M 51, M 63, NGC 5474, NGC 5477, UGC 9405, Ho IV, KUG1413+573, and others. Based on the TRGB method, we have d…