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A. I. Kopylov

Publications and source records attributed to A. I. Kopylov.

At least 19 recordsLinked to original sources
arXiv2017

Peculiar Motions of Galaxy Clusters in the Regions of Superclusters of galaxies

We present results of the study of peculiar motions of 57 clusters and groups of galaxies in the regions of the Corona Borealis (CrB), Bootes (Boo), Z5029/A1424, A1190, A1750/A1809 superclusters of galaxies and 20 galaxy clusters located beyond massive structures ($0.05<z<0.10$). Using the SDSS (Data Release 8) data, a sample of early-type galaxies was compiled in the systems under study, their fundamental planes were built, and relative distances and peculiar velocities were determined. Within the galaxy superclusters, significant peculiar motions along the line of sight are observed with rms deviations of $652\pm50$~km s$^{-1}$---in CrB, $757\pm70$~km s$^{-1}$---in Boo. For the most massive A2065 cluster in the CrB supercluster, no peculiar velocity was found. Peculiar motions of other galaxy clusters can be caused by their gravitational interaction both with A\,2065 and with the A2142 supercluster. It has been found that there are two superclusters projected onto each other in the region of the Bootes supercluster with a radial velocity difference of about 4000~km s$^{-1}$. In the Z5029/A1424 supercluster near the rich Z5029 cluster, the most considerable peculiar motions with a rms deviation of $1366\pm170$~km s$^{-1}$ are observed. The rms deviation of peculiar velocities of 20 clusters that do not belong to large-scale structures is equal to $0\pm20$~km s$^{-1}$. The whole sample of the clusters under study has the mean peculiar velocity equal to $83\pm130$~km s$^{-1}$ relative to the cosmic microwave background.

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arXiv2010

Investigation of the New Local Group Galaxy VV 124

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 and the velocity with which VV 124 falls into the Local Group is v_LG = -12+/-15 km/s. 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.

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arXiv2009

Analysis of a Sample of RC Catalog Objects in the Region Overlapping with the Areas Covered by FIRST and SDSS Surveys. II: Optical Identification with the SDSS Survey and USNO-B1 and 2MASS Catalogs

We report the results of optical identification of a sample of RC catalog radio sources with the FIRST and SDSS surveys. For 320 sources identified with NVSS and FIRST objects we perform optical identification with the SDSS survey. When selecting optical candidates we make maximum use of the information about the structure of radio sources as provided by the FIRST survey images. We find optical candidates for about 80% of all radio sources.

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arXiv2009

Analysis of the RC catalog sample in the region overlapping with the regions of the FIRST and SDSS surveys: I. Identification of sources with the VLSS, TXS, NVSS, FIRST, and GB6 catalogs

Radio sources of the RC catalog produced in 1980--1985 at RATAN-600 radio telescope based on a deep survey of a sky strip centered on the declination of the SS 433 source are optically identified in the region overlapping with FIRST and SDSS surveys (about 132 square degrees). The NVSS catalog was used as the reference catalog for refining the coordinates of the radio sources. The morphology is found for about 75% of the objects of the sample and the ratio of single, double and multicomponent radio sources is computed based on FIRST radio maps. The 74, 365, 1400, and 4850 MHz data of the VLSS, TXS, NVSS, FIRST, and GB6 catalogs are used to analyze the shape of the spectra.

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arXiv2008

Comparison of clustering properties of observed objects and dark matter halos on different mass and spatial scales

We investigate the large-scale distribution of galaxy clusters taken from several X-ray catalogs. Different statistics of clustering like the conditional correlation function (CCF) and the minimal spanning tree (MST) as well as void statistics were used. Clusters show two distinct regimes of clustering: 1) on scales of superclusters (~40/h Mpc) the CCF is represented by a power law; 2) on larger scales a gradual transition to homogeneity (~100/h Mpc) is observed. We also present the correlation analysis of the galaxy distribution taken from DR6 SDSS main galaxy database. In case of galaxies the limiting scales of the different clustering regimes are 1)10-15/h Mpc; 2) 40-50/h Mpc. The differences in the characteristic scales and scaling exponents of the cluster and galaxy distribution can be naturally explained within the theory of biased structure formation. We compared the density contrasts of inhomogeneities in the cluster and galaxy distributions in the SDSS region. The estimation of the relative cluster-galaxy bias gives the value b = 5 +/- 2. The distribution of real clusters is compared to that of simulated (model) clusters (the MareNostrum Universe simulations). We selected a cluster sample from 500/h Mpc simulation box with WMAP3 cosmological parameters and sigma_8 = 0.8. We found a general agreement between the distribution of observed and simulated clusters. The differences are mainly due to the presences of the Shapley supercluster in the observed sample. On the basis of SDSS galaxy sample we study properties of the power law behavior showed by the CCF on small scales. We show that this phenomenon is quite complex, with significant scatter in scaling properties, and characterized by a non-trivial dependence on galaxy properties and environment.

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arXiv2007

On the Photometric Redshift Estimates for FR II Radio Galaxies

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.

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arXiv2007

RC J0311+0507: A Candidate for Superpowerful Radio Galaxies in the Early Universe at Redshift z=4.514

A strong emission line at 6703A has been detected in the optical spectrum for the host galaxy (R=23.1) of the radio source RC J0311+0507 (4C+04.11). This radio galaxy, with a spectral index of 1.31 in the frequency range 365-4850 MHz, is one of the ultrasteep spectrum objects from the deep survey of a sky strip conducted with RATAN-600 in 1980-1981. We present arguments in favor of the identification of this line with Lyαat redshift z=4.514. In this case, the object belongs to the group of extremely distant radio galaxies of ultrahigh radio luminosity (P_{1400}=1.3 x 10^{29}W Hz^{-1}). Such power can be provided only by a fairly massive black hole (~10^9M_\sun}) that formed in a time less than the age of the Universe at the observed z(1.3 Gyr) or had a primordial origin.

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arXiv2002

Results of investigation of radio galaxies of the survey "Cold": photometry, colour redshifts and the age of the stellar population

BVRI data for the majority of the objects of the RC catalogue with steep spectra and $m_R<24^m$ are presented. These data have been used to estimate colour redshifts and the age of stellar systems of host galaxies. By way of example of distant radio galaxies it is shown that this approach gives an accuracy of redshift estimates close to that for field galaxies ($\sim20$ %). The age estimates are less confident, however, the lower age limit for not too distant ($z<1.5$) objects is determined quite reliably. Several galaxies have been detected that have an age above that of the Universe at the given $z$ in a simple CDM model of the Universe. A possibility of using such objects to specify the part played by ``dark energy'' is discussed. This paradox disappears in a model with the $Λ$-term equal to 0.6--0.8.

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arXiv2001

Photometric study of radio galaxies in RATAN--600 "Cold" survey

About 100 steep spectrum radio sources from the RATAN--600 RC catalog were mapped by the VLA and identified with optical objects down to 24$^m$--25$^m$ in the R band using the 6 m telescope. An updated list of calibrators with known redshifts of the same class RGs was compiled to evaluate the accuracy of photometric redshifts estimates. BVRI photometry for 60 RC objects was performed with the 6 m telescope, and by standard model fitting we have estimated colour redshifts and ages of stellar population of host gE galaxies. The mean redshift of FRII RGs from the RC list happened to be $\approx$1. Several objects were found in which active star formation began in the first billion years after the Big Bang.

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arXiv2001

Investigation of clustering of galaxies, clusters and superclusters by the method of correlation Gamma-function

Using the apparatus of correlation Gamma-function (``conditional density''), we have analyzed spatial clustering of objects from several different samples of galaxies, clusters and superclusters. On small scales the distribution of objects obeys a power law drop of density with a power index of 0.9--1.5. On a scale of ~30 Mpc for independent samples of bright galaxies and clusters of galaxies we have detected a pronounced break in the slope of the Gamma-function with a power index decreasing to ~0.3. The clustering is much less pronounced in the region from 40 to 100 Mpc, and there is reason to suppose that the distribution of objects changes to homogeneous on scales larger than 100 Mpc. This is indicated by the slope of the Gamma-function close to 0 for a sample of rich clusters of galaxies up to 250 Mpc. The slope of the Gamma-function prior to the break, which characterizes the degree of clustering of matter, changes essentially and in a complex manner when passing to brighter (massive) objects. This suggests that the large-scale structure of the visible Universe even on small scales is considerably more complex than the fractal distribution described by one dimension (monofractal).

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arXiv2000

RATAN-600 - VLA - BTA-6m ("BIG TRIO") Project: multicolour studying of distant radio galaxies

Powerful radio galaxies belong to the population of massive stellar systems that can be picked at high redshifts. With measured redshift, morphology and age determination these objects can help greatly in understanding of the way of formation and evolution of giant elliptical galaxies with massive Black Holes in the Early Universe. We presents some recent results of study of the sample of 105 faint steep spectrum radio sources from RATAN-600 RC catalogue. All the objects has been mapped with the VLA and optical identification have been carried out with the 6m BTA telescope. Using multicolour CCD photometry in B,V,R_c,I_c bands photometric redshift and age of stellar population are estimated for a subsample of 50 FRII and CSS radio galaxies. RC J0105+0501 is a very probable candidate for radio galaxy at z ~ 3.5. Distribution of objects on colour-colour and magnitude-redshift diagrams shows a rough agreement with expectations of theoretical models of SED evolution for giant elliptical galaxies. On the [m_R - z_{phot}] diagram two populations of faint (m_R = 22^m-24^m) radio galaxies are possibly revealed. The first population at z~ 1 consists of mainly old (a half with age >= 5 Gyr) and large (LAS~20") objects, the second one at z = 1.5 - 3.5 includes both younger (<= 3 Gyr) and smaller (LAS ~ 5") objects. There are 12 more faint or still undetected (m_R >= 24.5^m) sources in the sample which may presumably be a very distant radio galaxies (z>3.5) or intermediate redshift old or dusty ones.

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arXiv1999

RC J1148+0455 identification: gravitational lens or group of galaxies ?

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 radio source center is situated in a group of 8 galaxies of about 24$^m$ in the R-filter. The possible explanations of the complex structure of radio components are considered.

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arXiv1999

The software system "Evolution of radio galaxies"

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 (GISSEL'96 (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.

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arXiv1999

5 radio sources of the Zenith survey at RATAN-600: VLA maps, radio spectra and optical identification

VLA maps obtained at 1.4 GHz with a resolution of 2\farcs5$\times$2\arcsec for three sources and 6\farcs5$\times$2\farcs3 for two sources detected in the RATAN-600 Zenith survey of 1988 have been analyzed. All five objects have an extended structure. Continuous radio spectra of these objects prepared by using the CATS database and RATAN-600 observations are given. All five objects have linear steep spectra ($α< -0.65$). Using APM database and DSS we have found three candidates for identification. Two radio sources have been observed with the 6 m telescope. The nature of the studied objects, one of which is classified as QSO (BSO) and two others as galaxies, is discussed. One of the radio sources, RZ5, being a merging group of one large and several small galaxies, may have appeared in this process.

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arXiv1998

BVRcIc photometry of GRB970508 optical remnant: May-August, 1997

We present the results of photometric observations of the variable optical source associated to the remnant of the gamma-ray burst GRB970508 performed at SAO RAS (Russia) from May to August 1997. The observations were carried out with the standard (Johnson-Kron-Cousins) photometric BVRcIc system using the 1-meter and 6-meter telescopes. The brightness of the optical source increased from Rc=21.19 (May 9.75 UT) to Rc=19.70 (May 10.77 UT), whereupon it was decaying in all the four BVRcIc bands during about one month after the burst. Between the 3rd and the 6th night after the GRB970508 event, the flux decrease of the optical source follows an exponential law in all the four bands. In that period the broad-band spectrum of the object does not change and can be approximately described by a power with index -1.1. The subsequent observations showed a reduction of the source brightness decrease rate in all bands. The source flux decay after the maximum in the Rc band is well described by a single power-law with index -1.171 for the whole set of observations during 86 days. In the other bands the decay seems to slow down from the 31th day onwards. In particular, in the Ic band the source magnitude is about 23.1 from the 36th day after the GRB to the end of the observations (August 4, 1997).

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arXiv1997

Multicolor photometry of the GRB970508 optical remnant

We report results of follow-up multicolor photometry of the optical variable source that is a probable remnant of the gamma-ray burst GRB970508 discovered by the BeppoSAX satellite (IAUC 6649). Observations were carried out in Johnson-Kron-Cousins $ BVR_cI_c system with the 1-m and 6-m telescopes of SAO RAS. Between the 2nd and the 5th day after the burst a fading of the remnant is well fitted with an exponential law in all four bands. During this period the `broadband spectrum' of the object was unchanged and can be approximated by a power-law, F_ν\proptoν^{-1.1}. After the 5th day the decline of brightness is slowed down. In the R_c band until the 32nd day, the light curve can be described by a power-law relation, F_t \propto t^{-1.2}.

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