Papers by Alexander Kopylov
Monthly Notices of the Royal Astronomical Society, 1980
Astrophysical Bulletin, 2017
We study the variations of the properties of groups of galaxies with dynamical masses of 1013M⊙ 0... more We study the variations of the properties of groups of galaxies with dynamical masses of 1013M⊙ 0.027, and is located in the regions of the following superclusters of galaxies: Hercules, Leo, Bootes, Ursa Major, and Corona Borealis. Using the archived data of the SDSS and 2MASX catalogs, we determined the concentration of galaxies in the systems by measuring it as the inner density of the group within the distance of the fifth closest galaxy from the center brighter than MK = −23.m 3. We also measured the magnitude gap between the first and the fourth brightest galaxies ΔM14 located within one half of the selected radius R200, the fraction of early-type galaxies, and the ratio of bright dwarf galaxies (Mr = [−18.m 5,−16.m 5]) to giant galaxies (Mr < −18.m 5) (DGR) within the radius R200. The main aim of the investigation is to find among these characteristics the ones that reflect the evolution of groups of galaxies.We determined that the ratio of bright dwarf galaxies to early-type giant galaxies on the red sequence depends only on the x-ray luminosity: the DGR increases with luminosity. The fraction of early-type galaxies in the considered systems is equal, on average, to 0.65 ± 0.01, and varies significantly for galaxies with σ200 < 300 kms−1. Based on the luminosity of the brightest galaxy, the magnitude gap between the first and the fourth brightest galaxies in the groups, and on model computations of these parameters, we selected four fossil group candidates: AWM4, NGC0533, NGC0741, and NGC6098 (where the brightest galaxy is a double).We observe no increase in the number of faint galaxies (the α parameter of the Schechter function is less than 1) in our composite luminosity function (LF) for galaxy systems with z < 0.027 in the MK = [−26m,−21.m 5] range, whereas earlier we obtained α > 1 for the LF of the Hercules and Leo superclusters of galaxies.
Astronomical & Astrophysical Transactions, 1999
We present new limits on the small scale 3 K emission anisotropy. At scales of l°-3.3° all seven ... more We present new limits on the small scale 3 K emission anisotropy. At scales of l°-3.3° all seven harmonics have amplitudes below 10~5 in AT/T at our wavelength of 7.6 cm. At the 6.1xl0 3 to 17.5xl0 3 (rad _l) scale, this limit is about 2.8xl0~* (at 2.7 cm wavelength) and the observations may be fully explained by contributions from discrete sources. The low baryonic content of the Universe and present limit on the AT/T at the horizon scale suggest that (AM/M)» rav j^a t j n g << (AM/M){,aryonic• ^e speculate that the 3 K anisotropy measurements prove a) the existence of the dark matter, b) the nonbaryonic nature of this dark matter and c) that the space distribution of this matter is much more homogeneous than that of the visible one.
Astronomical & Astrophysical Transactions, 2000
The project of the informational system creation on the problem of evolution of radio galaxies is... more The project of the informational system creation on the problem of evolution of radio galaxies is described. This system, being developed at present, will allow a user to operate with simulated curves of spectral energy distributions (SED) and to estimate ages and redshifts by photometrical data. Authors use SEDs of several models (GISSEL96 (Bruzual, Charlot, 1996), PEGASE (Fioc, Rocca-Volmerange, 1996) and Poggianti(1996)) for different types of galaxies. Planned modes of access, formats of output result and additional functions are described.
Using all the data available in the literature on colour characteristics of host galaxies associa... more Using all the data available in the literature on colour characteristics of host galaxies associated with distant (z > 1) radio galaxies, a possibility has been investigated of using two evolutionary models of stellar systems (PEGASE and Poggianti) to evaluate readshifts and ages of stellar systems in these galaxies. Recommendations for their applications are given.
Astronomy Letters, 2005
Using the photometric data on FR II radio galaxies obtained in the Big Trio Program and data from... more Using the photometric data on FR II radio galaxies obtained in the Big Trio Program and data from other sources, we confirmed the stable correlation between the spectroscopic and photometric redshifts up to z ∼ 4 determined from the evolutionary synthetic spectra of elliptical galaxies. This is a confirmation for the theoretical predictions of the existence of a stellar population at high redshifts and its subsequent evolution corresponding to the population of giant elliptical galaxies.
Astronomy Letters, 2006
We study the infrared (K s band) properties of clusters of galaxies in the Ursa Major supercluste... more We study the infrared (K s band) properties of clusters of galaxies in the Ursa Major supercluster using data from 2MASS (Two-Micron All-Sky Survey) and SDSS (Sloan Digital Sky Survey). We identified three large filaments with mean redshifts of z = 0.051, 0.060, and 0.071. All clusters of the supercluster are located in these filaments. We determined the total K s-band luminosities and masses for 11 clusters of galaxies within comparable physical regions (within a radius R 200 close to the virial radius) using a homogeneous method. We constructed a combined luminosity function for the supercluster in this region, which can be described by the Schechter function with the following parameters: M * K = −24 m .50 and α = −0.98. The infrared luminosities of the clusters of galaxies correlate with their masses; the M/L K ratios of the systems increase with their masses (luminosities), with most of the Ursa Major clusters of galaxies (particularly the richer ones) closely following the relations derived previously for a large sample of clusters and groups of galaxies. The total mass-to-infrared-luminosity ratio is 52 M ⊙ /L ⊙ for six Abell clusters and 49 M ⊙ /L ⊙ for all of the clusters, except Anon2.
Astronomy Letters, 2010
We present the results of our stellar photometry and spectroscopy for the new Local Group galaxy ... more We present the results of our stellar photometry and spectroscopy for the new Local Group galaxy VV 124 (UGC 4879) obtained with the 6-m BTA telescope. The presence of a few bright supergiants in the galaxy indicates that the current star formation process is weak. The apparent distribution of stars with different ages in VV 124 does not differ from the analogous distributions of stars in irregular galaxies, but the ratio of the numbers of young and old stars indicates that VV 124 belongs to the rare Irr/Sph type of galaxies. The old stars (red giants) form the most extended structure, a thick disk with an exponential decrease in the star number density to the edge. Definitely, the young population unresolvable in images makes a great contribution to the background emission from the central galactic regions. The presence of young stars is also confirmed by the [O III] emission line visible in the spectra that belongs to extensive diffuse galactic regions. The mean radial velocity of several components (two bright supergiants, the unresolvable stellar population, and the diffuse gas) is v h = −70 ± 15 km s −1 and the velocity with which VV 124 falls into the Local Group is v LG = −12 ± 15 km s −1. We confirm the distance to the galaxy (D = 1.1 ± 0.1 Mpc) and the metallicity of red giants ([Fe/H] = −1.37) found by Kopylov et al. (2008). VV 124 is located on the periphery of the Local Group approximately at the same distance from M 31 and our Galaxy and is isolated from other galaxies. The galaxy LeoA nearest to it is 0.5 Mpc away.
Astronomy and Astrophysics, 2002
We present the results of a study of streaming motion of galaxy clusters around the Giant Void (α... more We present the results of a study of streaming motion of galaxy clusters around the Giant Void (α ≈ 13 h , δ ≈ 40 • , z ≈ 0.11 and a diameter of 300 Mpc) in the distribution of rich Abell clusters. We used the Kormendy relation as a distance indicator taking into account galaxy luminosities. Observations were carried out in Kron-Cousins Rc system on the 6 m and 1 m telescopes of SAO RAS. For 17 clusters in a spherical shell of 50 Mpc in thickness centered on the void no significant diverging motion (expected to be generated by the mass deficit in the void) has been detected. This implies that cosmological models with low Ωm are preferred. To explain small mass underdensity inside the Giant Void, a mechanism of void formation with strong biasing is required.
Astronomy & Astrophysics, 2004
We present the results of optical identification of 248 interplanetary scintillating (IPS) radio ... more We present the results of optical identification of 248 interplanetary scintillating (IPS) radio sources from the Pushchino Survey (PS) in the area of 0.11 sr with the center at α = 10 h 28 m , δ = +41 •. All 260 counterparts of IPS radio sources from the 7C and FIRST catalogues, which had been found in Paper I, were considered. We used USNO-B1.0 catalogue (limiting magnitude m R ≈ 21) for the optical identification and searched the literature to find optical data for fainter objects. Photometric and spectroscopic observations were conducted on the 1 m and 6 m telescopes of SAO RAS. Optical magnitudes or deep limits for 22 objects and redshifts for 26 ones have been obtained. In total, we collected optical data for 116 (68 with redshift) counterparts of the PS radio sources. For the subsample of the PS quasars (41 objects) the redshift distribution was compared to those of several other samples of quasars (BRL, 3CRR, MQS, B3-VLA, 7CRS I-III and PKS 0.25 Jy) which have complete or nearly complete redshift information.
Astronomy and Astrophysics Supplement Series, 1999
We present direct imaging data of 22 ultra steep spectrum radio sources obtained at (or near) a s... more We present direct imaging data of 22 ultra steep spectrum radio sources obtained at (or near) a subarcsecond seeing. The basic sample of 40 double radio sources was selected from the RATAN-600 catalogue. The FRII-structure has been confirmed with VLA and preliminary optical identifications which come from the 6 m-telescope. As the RATAN-600 flux limit at 3.9 GHz (≈ 10 mJy) is fainter than that of major surveys, the sample may have high-z contents. This is also suggested by the faint magnitudes in the Hubble diagram. The final aim is to create a homogeneous sample of high-z radio galaxies in a well defined strip around the sky, with faint radio limit and subarcsecond morphology down to m R = 24. We could confirm 16 identifications down to m R ∼ 24. Most of the extended objects have multicomponent structures as expected from other surveys of high-redshift radio galaxies. We found five unresolved objects even with a subarcsecond seeing. Of the remaining six objects, three are extremely faint and the other three have such a complex environment that further observations are needed to confirm the optical identification.
Astronomical & Astrophysical Transactions, 2000
The structure of the radio source RC B1146+052 of the "Cold"catalogue is investigated by data of ... more The structure of the radio source RC B1146+052 of the "Cold"catalogue is investigated by data of the MIT-GB-VLA survey at 4850 MHz. This source belongs to the steep spectrum radio sources subsample of the RC catalogue. Its spectral index is α =-1.04. The optical image of this source obtained with 6m telescope is analysed. The possible explanations of the complex structure of radio components are considered.
Based on SDSS (Sloan Digital Sky Survey) and 2MASS (Two Micron All Sky Survey) data, we have inve... more Based on SDSS (Sloan Digital Sky Survey) and 2MASS (Two Micron All Sky Survey) data, we have investigated the structure of the Ursa Major (UMa) supercluster, near IR properties and peculiar motions in the system and its nearest neighbourhood. Three large filamentary structures (layers), with redshift ranges 0.045-0.055, 0.055-0.065, and 0.065-0.075, are identified in the supercluster. These layers are stretched along right ascension, do not overlap in the plane of the sky and contains almost all clusters that are identified in the UMa system (12 clusters). The infrared luminosities (total K-band light) of the clusters of galaxies, the M/LK ratios and total number of cluster members within radius R200 correlate with their masses (luminosities) closely following the relations derived previously for a large sample of clusters and groups of galaxies. The total scatter in the relations for UMa clusters are about a factor 2 smaller than for field clusters. This fact may indicates that fie...
Symposium - International Astronomical Union
With the aim to extend a sample of the distant radio objects, about 100 steep spectrum FRII radio... more With the aim to extend a sample of the distant radio objects, about 100 steep spectrum FRII radio galaxies (SS FRII RG) from the RATAN—600 RC catalog were mapped by the VLA1 and identified with optical objects down to R = 24m − 25m with the 6 m telescope. The mean estimated redshift of SS FRII RGs from the RC list happened to be greater than 1.5. BV RI photometry was made, and by standard model fitting we have estimated “colour” redshift and the age of stellar population of the parent gE galaxy in 50 cases. Several objects were found in which active star formation began in the first billion of years after the Big Bang.
Part 1 contains parameters in 74-4850MHz frequency range for 320 radio sources of the RC catalog.... more Part 1 contains parameters in 74-4850MHz frequency range for 320 radio sources of the RC catalog. After visual inspection of the sample on images of the NVSS and FIRST surveys we defined morphological type, number of FIRST counterparts of each source and angular size for multi-components sources, also refined coordinates of the RC catalog sources. We used GB6 images for
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Papers by Alexander Kopylov