A. V. Temirova

RC J0311+0507: A candidate for superpowerful radio galaxies in the early universe at redshift z = 4.514

A strong emission line at 6703 Å 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 Lyα at redshift z = 4.514. In this case, the object belongs to the group of extremely distant radio galaxies of ultrahigh radio luminosity (P1400 = 1.3 × 1029 W Hz−1). Such power can be provided only by a fairly massive black hole (∼109M⊙) that formed in a time less than the age of the Universe at the observed z (1.3 Gyr) or had a primordial origin.

RATAN-600 7.6-cm deep sky strip surveys at the declination of the SS433 source during the 1980–1999 period. Data reduction and the catalog of radio sources in the right-ascension interval 7h ≤ R.A. < 17h

We use two independent methods to reduce the data of the surveys made with RATAN600 radio telescope at 7.6 cm in 1988–1999 at the declination of the SS433 source. We also reprocess the data of the “Cold” survey (1980–1981). The resulting RCR (RATAN COLD REFINED) catalog contains the right ascensions and fluxes of objects identified with those of the NVSS catalog in the right-ascension interval 7 ≤ R.A. < 17. We obtain the spectra of the radio sources and determine their spectral indices at 3.94 and 0.5 GHz. The spectra are based on the data from all known catalogs available from the CATS, Vizier, and NED databases, and the flux estimates inferred from the maps of the VLSS and GB6 surveys. For 245 of the 550 objects of the RCR catalog the fluxes are known at two frequencies only: 3.94 GHz (RCR) and 1.4 GHz (NVSS). These are mostly sources with fluxes smaller than 30 mJy. About 65% of these sources have flat or inverse spectra (α > −0.5). We analyze the reliability of the results obtained for the entire list of objects and construct the histograms of the spectral indices and fluxes of the sources. Our main conclusion is that all 10–15 mJy objects found in the considered right-ascension interval were already included in the decimeter-wave catalogs.We use two independent methods to reduce the data of the surveys made with RATAN-600 radio telescope at 7.6 cm in 1988–1999 at the declination of the SS433 source. We also reprocess the data of the “Cold” survey (1980–1981). The resulting RCR (RATAN COLD REFINED) catalog contains the right ascensions and fluxes of objects identified with those of the NVSS catalog in the right-ascension interval 7h ≤ R.A. < 17h. We obtain the spectra of the radio sources and determine their spectral indices at 3.94 and 0.5 GHz. The spectra are based on the data from all known catalogs available from the CATS, Vizier, and NED databases, and the flux estimates inferred from the maps of the VLSS and GB6 surveys. For 245 of the 550 objects of the RCR catalog the fluxes are known at two frequencies only: 3.94 GHz (RCR) and 1.4 GHz (NVSS). These are mostly sources with fluxes smaller than 30mJy. About 65% of these sources have flat or inverse spectra (α > −0.5). We analyze the reliability of the results obtained for the entire list of objects and construct the histograms of the spectral indices and fluxes of the sources. Our main conclusion is that all 10–15 mJy objects found in the considered right-ascension interval were already included in the decimeter-wave catalogs.

Optical morphology of distant RATAN-600 radio galaxies from subarcsecond resolution NOT images

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 ra- dio sources was selected from the RATAN-600 catalogue. The FRII-structure has been conrmed with VLA and preliminary optical identications 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 sam- ple may have high-z contents. This is also suggested by the faint magnitudes in the Hubble diagram. The nal aim is to create a homogeneous sample of high-z radio galaxies in a well dened strip around the sky, with faint radio limit and subarcsecond morphology down to mR = 24. We could conrm 16 identications down to mR 24. Most of the extended objects have multicomponent struc- tures as expected from other surveys of high-redshift ra- dio galaxies. We found ve unresolved objects even with a subarcsecond seeing. Of the remaining six objects, three are extremely faint and the other three have such a com- plex environment that further observations are needed to conrm the optical identication.

Identification and properties of host galaxies of RCR radio sources

FIRST and NVSS radio maps are used to cross identify the radio sources of the RCR catalog, which is based on observational data obtained in several runs of the “Cold” survey, with the SDSS and DPOSS digital optical sky surveys and the 2MASS, LAS UKIDSS, and WISE infrared surveys. Digital images in various filters and the coadded gri-band SDSS images, red and infrared DPOSS images, JHK-band UKIDSS images, and JHK-band 2MASS images are analyzed for the sources with no optical candidates found in the above catalogs. Our choice of optical candidates was based on the data on the structure of the radio source, its photometry, and spectroscopy (where available). We found reliable identifications for 86% of the radio sources; possible counterparts for 8% of the sources, and failed to find any optical counterparts for 6% of the sources because their host objects proved to be fainter than the limiting magnitude of the corresponding surveys. A little over half of all the identifications proved to be galaxies; about one quarter were quasars, and the types of the remaining objects were difficult to determine because of their faintness. A relation between the luminosity and the radioloudness index was derived and used to estimate the 1.4 and 3.94 GHz luminosities for the sources with unknown redshifts. We found 3% and 60% of all the RCR radio sources to be FRI-type objects (L ≲ 1024 W/Hz at 1.4 GHz) and powerful FRII-type galaxies (L ≳ 1026.5 W/Hz), respectively, whereas the rest are sources including objects of the FRI, FRII, and mixed FRI-FRII types. Unlike quasars, galaxies show a trend of decreasing luminosity with decreasing flux density. Note that identification would be quite problematic without the software and resources of the virtual observatory.

Spectroscopy of Big Trio Objects Using the Scorpio Spectrograph of the 6-m Telescope of the Special Astrophysical Observatory

We present the results of spectroscopy of 71 objects with steep and ultra-steep spectra (α < −0.9, S ∝ να) from the “Big Trio” (RATAN-600-VLA-BTA) project, performed with the “Scorpio” spectrograph on the 6-m telescope of the Special Astrophysical Observatory (Russian Academy of Sciences). Redshifts were determined for these objects. We also present several other parameters of the sources, such as their R magnitudes, maximum radio sizes in seconds of arc, flux densities at 500, 1425, and 3940 MHz, radio luminosities at 500 and 3940 MHz, and morphology. Of the total number of radio galaxies studied, four have redshifts 1 ≤ z < 2, three have 2 ≤ z < 3, one has 3 ≤ z < 4, and one has z = 4.51. Thirteen sources have redshifts 0.7 < z < 1 and 15 have 0.2 < z < 0.7.Of all the quasars studied, five have redshifts 0.7 < z < 1, seven have 1 ≤ z < 2, four have 2 ≤ z < 3, and one has z = 3.57. We did not detect any spectral lines for 17 objects.

The software system ‘evolution of radio galaxies’

Abstract The project of the informational system creation on the problem of evolution of radio galaxies is described. This system, which is currently being developed, will allow a user to operate with simulated curves of spectral energy distributions (SED) and to estimate ages and red-shifts 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.

Search for variable sources using the data of Cold surveys in the right-ascension interval 2h ≤ RA ≤ 6h

We search for variable objects at 3.94 GHz in the 1988–1994 surveys within the right-ascension interval 2h ≤ RA ≤ 6h. In this study we continue to develop our technique for identifying variable radio sources in the Cold surveys. We identified a total of 195 radio sources in the available sky transit scans, and only 145 objects have their flux measured in two or more surveys. To check these radio sources for variability, we estimated the indices V of long-term variability, the relative variability amplitude Vχ, and the χ2 probability p. Among the 145 objects considered, 15 have positive long-term variability indices (V >0). Of these, five sources have χ2 probability p greater than 0.95. Three objects with p > 0.996 can be considered reliably variable sources, and two objects with probabilities 0.95 < p < 0.996 can be considered possibly variable sources. Eight objects prove to be reliably variable according to an analysis of our data combined with the flux measurements by other authors, performed within the framework of the 1980 survey. We draw the light curves for sources with positive long-term variability indices and perform optical identification of these objects.

RC J0105+0501: A radio galaxy with redshift z≈3.5

AbstractWe study the radio galaxy RC J0105+0501 by using observations with RATAN-600, VLA, and 6-m Special Astrophysical Observatory telescope. The radio source has a structure resembling the FRII type and the spectral index α=1.23; it is identified with a faint galaxy of

Spectral characteristics of faint radio sources of the KHOLOD survey

22\mathop .\limits^m 8