A Unified Catalog of Radio Objects Detected by NVSS, FIRST, WENSS, GB6, and SDSS
Amy E. Kimball, Željko Ivezić
备注：
42 pages, 22 figures, 8 tables; a version with high resolution figures is available at http://www.astro.washington.edu/users/akimball/radiocat/ . Published in the Astronomical Journal. Replacement comment: data URL has changed
(Abridged) We construct a catalog of radio sources detected by the GB6 (6 cm), FIRST and NVSS (20 cm), and WENSS (92 cm) radio surveys, and the SDSS optical survey. The 2.7 million entries in the publicly-available master catalog are comprised of the closest three FIRST to NVSS matches (within 30 arcsec) and vice-versa, and unmatched sources from each survey. Entries are supplemented by data from the other radio and optical surveys, where available. We perform data analysis a ~3000 deg^2 region of sky where the surveys overlap, which contains 140,000 NVSS-FIRST sources, of which 64,000 are detected by WENSS and 12,000 by GB6. About one third of each sample is detected by SDSS. An automated classification method based on 20 cm fluxes defines three radio morphology classes: complex, resolved, and compact. Radio color-magnitude- morphology diagrams for these classes show structure suggestive of strong underlying physical correlations. Complex and resolved sources tend to have a steep spectral slope (alpha ~ -0.8) that is nearly constant from 6 to 92 cm, while the compact class contains a significant number of flat-spectrum (alpha ~ 0) sources. In the optically-detected sample, quasars dominate the flat-spectrum compact sources while steep-spectrum and resolved objects contain substantial numbers of both quasars and galaxies. Differential radio counts of quasars and galaxies are similar at bright flux levels (>100 mJy at 20 cm), while at fainter levels the quasar counts are significantly reduced below galaxy counts. The optically-undetected sample is strongly biased toward steep-spectrum sources. In samples of quasars and galaxies with SDSS spectra, we find that radio properties such as spectral slope, morphology, and radio loudness are correlated with optical color and luminosity.
I have searched the Westerbork Northern Sky Survey (WENSS) source list for detections of known radio pulsars. A source with a flux density greater than five times the local noise level is found near the positions of 25 pulsars. The probability that one out of these 25 sources is a chance coincidence is about 10%. I have looked at the WENSS maps of the non-detected pulsars. A flux density between three and five times the local noise level is found near the positions of 14 of these non-detected pulsars. There is a 50 percent probability that (at least) one of these marginal detections is just a …
We discuss the panchromatic properties of 99,088 galaxies selected from the SDSS Data Release 1 spectroscopic sample (a flux-limited sample for 1360 deg^2). These galaxies are positionally matched to sources detected by ROSAT, GALEX, 2MASS, IRAS, GB6, FIRST, NVSS and WENSS. We find strong correlations between the detection fraction at other wavelengths and optical properties such as flux, colors, and emission-line strengths. Using GALEX, SDSS, and 2MASS data, we construct the UV-IR broad-band spectral energy distributions for various types of galaxies, and find that they form a nearly one-para…
We have formed a complete sample of 26 low redshift (z < 0.3) giant radio galaxies (GRGs) from the WENSS survey, selected at flux densities above 1 Jy at 325 MHz. We present 10.5-GHz observations with the 100-m Effelsberg telescope of 18 sources in this sample. These observations, together with similar data of the remaining eight sources, are combined with data from the WENSS, NVSS and GB6 surveys to study the radio properties of the lobes of these sources at arcminute resolution. We investigate radio source asymmetries, equipartition energy densities in the lobes, the presence of lobe pressur…
The authors describe the largest existing publicly accessible radio source database CATS (``astrophysical CATalogues Supporting system''; http://cats.sao.ru). CATS contains more than 300 catalogues of objects detected in different (but mostly radio) wavelength ranges. These include catalogues from the largest existing surveys, like NVSS, FIRST, WENSS, TXS, GB6, IRAS, ROSAT, PGC, MCG, etc. Thus CATS allows to draw samples of objects to study a great variety of astrophysical problems. CATS also includes all of the largest low-frequency catalogues published so far : UTR(10--25 MHz), Culgoora (80,…
Very deep 4.9 GHz observations with the VLA are used to supplement available radio maps at the frequencies of 325 MHz (WENSS survey) and 1.4 GHz (NVSS survey) in order to study the synchrotron spectra and radiative ages of relativistic particles in the extended lobes of distant giant radio galaxies selected from the sample of Machalski et al. (2001).
We positionally match the 6 cm GB6, 20 cm FIRST and NVSS, and 92 cm WENSS radio catalogs and find 16,500 matches in ~3,000 deg2 of sky. Using this unified radio database, we construct radio "color-magnitude-morphology" diagrams and find that they display a clear structure, rather than a random scatter. We propose a simple, yet powerful, method for morphological classification of radio sources based on FIRST and NVSS measurements. For a subset of matched sources, we find optical identifications using the SDSS Data Release 1 catalogs, and separate them into quasars and galaxies. Compact radio so…
We measure the angular correlation function of radio galaxies selected by the 843 MHz Sydney University Molonglo Sky Survey (SUMSS). We find that the characteristic imprint of large-scale structure is clearly detectable, and that the survey is very uniform. Through comparison with similar analyses for other wide-area radio surveys - the 1400 MHz NRAO VLA Sky Survey (NVSS) and the 325 MHz Westerbork Northern Sky Survey (WENSS) - we are able to derive consistent angular clustering parameters, including a steep slope for the clustering function, $w(θ) \propto θ^{-1.1}$. We revise upwards previous…
Since radio sources with Ultra Steep Spectra (USS; alpha <~ -1.30; S ~ nu^alpha) are efficient tracers of high redshift radio galaxies (HzRGs), we have defined three samples of such USS sources using the recently completed WENSS, TEXAS, MRC, NVSS and PMN radio-surveys. Our combined sample contains 669 sources with S_1400 > 10 mJy and covers virtually the entire sky outside the Galactic plane (|b|>15). For our 2 largest samples, covering declination > -35, we selected only sources with angular sizes Theta < 1'. For 410 sources, we present radio-maps with 0.3" to ~5" resolution from VLA and ATCA…
In this paper we constrain the evolution in the comoving space density for low-luminosity (typically FRI) radio sources as a function of cosmic epoch by matching deep radio surveys (WENSS, FIRST and NVSS) with the Sloan Digital Sky Survey (SDSS). This results in 1014 matched radio sources covering an effective area of 0.217 sr, 686 with L(325 MHz) < 10^25 W/Hz/sr, which is an order of magnitude larger than any previous study at these luminosities. Using the non-parametric V/Vmax test we show that low-luminosity radio sources evolve differently to their more powerful, predominantly FRII, counte…
The 352 MHz Westerbork In the Southern Hemisphere (WISH) survey is the southern extension of the WENSS, covering 1.60 sr between -9 < DEC < -26 to a limiting flux density of ~18 mJy (5sigma). Due to the very low elevation of the observations, the survey has a much lower resolution in declination than in right ascension (54" x 54"cosec(DEC)). A correlation with the 1.4 GHz NVSS shows that the positional accuracy is less constrained in declination than in right ascension, but there is no significant systematic error. We present a source list containing 73570 sources. We correlate this WISH catal…
We summarize the detection rates at wavelengths other than optical for \~99,000 galaxies from the Sloan Digital Sky Survey (SDSS) Data Release 1 ``main'' spectroscopic sample. The analysis is based on positional cross-correlation with source catalogs from ROSAT, 2MASS, IRAS, GB6, FIRST, NVSS and WENSS surveys. We find that the rest-frame UV-IR broad-band galaxy SEDs form a remarkably uniform, nearly one parameter, family. As an example, the SDSS u and r band data, supplemented with redshift, can be used to predict K band magnitudes measured by 2MASS with an rms scatter of only 0.2 mag; when me…
In this paper we show normalized differential source counts n(S) at 408 MHz and 1.4 GHz of radio sources separately for FRI and FRII classes with extended and compact morphologies. The maps from the FIRST, NVSS, and WENSS surveys are used to define the source morphology and flux density. The counts provide a basis for a direct test as well as constraining the cosmological evolution of powerful extragalactic radio sources in terms of the dual-population model (Jackson & Wall 1999), where radio sources of Fanaroff-Riley (1974) types I and II are regarded as two physically separate types of activ…
We report on the first wide-field, very long baseline interferometry (VLBI) survey at 90 cm. The survey area consists of two overlapping 28 deg^2 fields centred on the quasar J0226+3421 and the gravitational lens B0218+357. A total of 618 sources were targeted in these fields, based on identifications from Westerbork Northern Sky Survey (WENSS) data. Of these sources, 272 had flux densities that, if unresolved, would fall above the sensitivity limit of the VLBI observations. A total of 27 sources were detected as far as 2 arcdegrees from the phase centre. The results of the survey suggest that…
We search fora dichotomy/bimodality between Radio Loud (RL) and Radio Quiet (RQ) Type 1 Active Galactic Nuclei (AGN). We examine several samples of SDSS QSOs with high S/N optical spectra and matching FIRST/NVSS radio observations. We use the radio data to identify the weakest RL sources with FRII structure to define a RL/RQ boundary which corresponds to log L$_{1.4GHz}$=31.6 ergs s$^{-1}$ Hz$^{-1}$. We measure properties of broad line H$β$ and FeII emission to define the optical plane of a 4DE1 spectroscopic diagnostic space. The RL quasars occupy a much more restricted domain in this optical…
The study of the radio properties of the AMIGA sample is intended to characterize the radio continuum emission for a sample least affected by local environment, thus providing a reference against which less isolated and interacting samples can be compared. Radio continuum data at 325, 1420 and 4850 MHz were extracted from the WENSS, NVSS/FIRST and GB6 surveys, respectively. We focus on the complete AMIGA subsample composed of 719 galaxies. Comparison between the NVSS and FIRST detections indicates that the radio continuum is coming from disk-dominated emission in spiral galaxies, in contrast t…
We have started a search for High Redshift Radio Galaxies (HZRGs) in an area covering 7 sr by selecting a sample of Ultra Steep Spectrum (USS) sources with a low flux density cut-off S(1400 MHz) > 10 mJy and a steep spectral index cut-off of alpha < -1.3 (S ~ nu**alpha) from the WENSS, NVSS and TEXAS surveys. Our first results for 27 sources show that we are almost twice as effective in finding HZRGs than than surveys of relatively bright radio sources with a spectral index cut-off of alpha < -1.0. The redshift distribution is consistent with an extension of the z - alpha relation to alpha < -…
We investigate the correlation of gravitational lensing of the cosmic microwave background (CMB) with several tracers of large-scale structure, including luminous red galaxies (LRGs), quasars, and radio sources. The lensing field is reconstructed based on the CMB maps from the Wilkinson Microwave Anisotropy Probe (WMAP) satellite; the LRGs and quasars are observed by the Sloan Digital Sky Survey (SDSS); and the radio sources are observed in the NRAO VLA Sky Survey (NVSS). Combining all three large-scale structure samples, we find evidence for a positive cross-correlation at the $2.5σ$ level ($…
We describe the current status of CATS, a publicly accessible database (web-server http://cats.sao.ru) allowing one to search in hundreds of catalogs of astronomical objects discovered all along the electromagnetic spectrum. Our emphasis is mainly laid on catalogs of radio continuum sources observed from 30 to 15000 MHz, secondly on catalogs of objects such as radio and active stars, planetary nebulae, HII regions, supernova remnants (SNR), pulsars, nearby galaxies, AGN and quasars. CATS also includes the catalogs from the largest extragalactic surveys, like NVSS, FIRST, WENSS, VLSS, TXS, GB6,…
We present an overview of unbiased studies of diffuse extragalactic radio sources. We use a previously developed filtering technique to remove compact sources from large surveys such as WENSS, WISH, and NVSS and examine the residual diffuse emission. A search of these residuals, unbiased by optical or X-ray selection, has uncovered a wide variety of diffuse sources, including those associated with groups of galaxies, ``blank'' fields, and previously unrecognized diffuse radio galaxy emission, as well as halos and relics of rich clusters. A second, targeted survey of the brightest X-ray cluster…
We investigate the X-ray properties of the color-selected radio-quiet quasars (RQQs) in the Sloan Digital Sky Survey (SDSS) Early Data Release using ROSAT, Chandra, and XMM-Newton data. In the 0.16-6.28 redshift range, 136 RQQs have X-ray detections (69 from the ROSAT All-Sky Survey, RASS), while for 70 RQQs X-ray upper limits are obtained. The well-defined selection method utilized by the SDSS, coupled with the tight radio constraints from the FIRST/NVSS surveys, allow us to define a representative sample of optically selected RQQs whose broad-band spectral energy distributions (characterized…
Context. Although Blazars are a small fraction of the overall AGN population they are expected to be the dominant population of extragalactic sources in the hard X-ray and gamma-ray bands and have been shown to be the largest contaminant of CMB fluctuation maps. So far the number of known blazars is of the order of several hundreds, but the forthcoming AGILE, GLAST and Planck space observatories will detect several thousand of objects of this type. Aims. In preparation for these missions it is necessary to identify new samples of blazars to study their multi-frequency characteristics and stati…
We present the results of new observations of the enigmatic radio source B1144+352 with the WSRT at 1.4 GHz. The WENSS and NVSS surveys have revealed faint extended radio structures on Mpc-scales. We have investigated these large-scale radio components. One of the radio structures has a leading hotspot and we conclude that this structure is a large radio lobe associated with the GPS source. The other contains two separate radio sources which are superposed on the sky: A low-power radio source at a similar redshift (z=0.065) to the GPS host galaxy and an extended radio lobe, which we believe is…
We present the results of a detailed analysis of the newly discovered 15 arcmin large FRII-type radio galaxy WNB 0313+683. It has a redshift of 0.0901 +/- 0.0002 and a projected linear size of 2.0 Mpc. Using multi-frequency radio data from the WENSS and NVSS surveys, the VLA, the WSRT and the 100m Effelsberg telescope, we have derived the age of the source (1.4 +/- 0.1 x 10^8 yrs) and the particle densities around the two radio lobes (>1.6 x 10^(-6) per cubic cm for the southern lobe and >5.8 x 10^(-7) per cubic cm for the northern). From optical spectroscopy we find that the H$α$ emission lin…
We use the distribution of gravitationally-lensed image separations observed in the Cosmic Lens All-Sky Survey (CLASS) and the PMN-NVSS Extragalactic Lens Survey (PANELS), which are (nearly) complete for the image separation range $0''.3 \le Δθ\le 6''$, to constrain a model velocity dispersion function (VF) of early-type galaxies. Assuming a current concordance cosmological model and adopting a singular isothermal ellipsoid (SIE) model for galactic potentials, we consider constraining both a characteristic velocity dispersion (parameter $σ_*$) and the shape of the function (parameters $α$ and …
Up till now very few dying sources were known, presumably because the dying phase is short at centimeter wavelengths. We therefore have tried to improve the statistics on sources that have ceased to be active, or are intermittently active. The latter sources would partly consist of a fossil radio plasma left over from an earlier phase of activity, plus a recently restarted core and radio jets. Improving the statistics of dying sources will give us a better handle on the evolution of radio sources, in particular the frequency and time scales of radio activity. We have used the WENSS and NVSS su…
Using the radio observations by FIRST and NVSS, we build a sample of 151 radio variable quasars selected from the Sloan Digital Sky Survey Data Release 3 (SDSS DR3). Six (probably another two) among them are classified as broad absorption line (BAL) quasars, with radio flux variations of a few 10 percent within 1.5-5 years. Such large amplitudes of the variations imply brightness temperatures much higher than the inverse Compton limits (10$^{12}$ K) in all the BAL quasars, suggesting the presence of relativistic jets beaming toward the observer. The angle between the outflow and the jet is con…
A sample of 2712 radio-luminous galaxies is defined from the second data release of the Sloan Digital Sky Survey (SDSS) by cross-comparing the main spectroscopic galaxy sample with two radio surveys: the NRAO VLA Sky Survey (NVSS) and the Faint Images of the Radio Sky at Twenty centimetres (FIRST) survey. The comparison is carried out in a multi-stage process and makes optimal use of both radio surveys by exploiting the sensitivity of the NVSS to extended and multi-component radio sources in addition to the high angular resolution of the FIRST images. A radio source sample with 95% completenes…
We cross-correlate large scale structure (LSS) observations from a number of surveys with CMB anisotropies from WMAP to investigate the Integrated Sachs-Wolfe (ISW) effect as a function of redshift, covering z~0.1-2.5. Our main goal is to go beyond reporting detections towards developing a reliable likelihood analysis that allows one to determine cosmological constraints from ISW observations. With this in mind we spend a considerable amount of effort in determining the redshift-dependent bias and redshift distribution b(z)*dN/dz of these samples by matching with spectroscopic observations whe…
Large digital sky surveys, over a broad range of wavelengths, both from the ground and from space observatories, are becoming a major source of astronomical data. Some examples include the Sloan Digital Sky Survey (SDSS) and the Digital Palomar Observatory Sky Survey (DPOSS) in the visible, the Two-Micron All-Sky Survey (2MASS) in the near-infrared, the NRAO VLA Sky Survey (NVSS) and the Faint Images of the Radio Sky at Twenty centimeters (FIRST) in the radio. Many others surveys are planned or expected, in addition to the previously named surveys. While most surveys are exclusively imaging, l…
A catalogue of 14453 radio-loud AGN with 1.4 GHz fluxes above 3.5 mJy in the redshift range 0.4<z<0.8, has been constructed from the cross-correlation of the NVSS and FIRST radio surveys with the MegaZ-LRG catalogue of luminous red galaxies derived from Sloan Digital Sky Survey imaging data. New techniques were developed for extending the cross-correlation algorithm to FIRST detections that are below the nominal 1 mJy S/N limit of the catalogued sources. We estimate a reliability of ~98.3%, and completeness level (for LRGS) of about 95% for our new catalogue. We present a new determination of …
We have combined optical data from the 2dF-SDSS Luminous Red Galaxy and QSO (2SLAQ) redshift survey with radio measurements from the 1.4 GHz VLA FIRST and NVSS surveys to identify a volume-limited sample of 391 radio galaxies at redshift 0.4<z<0.7. By determining an accurate radio luminosity function for early-type galaxies in this redshift range, we can investigate the cosmic evolution of the radio-galaxy population over a wide range in radio luminosity. The low-power radio galaxies in our LRG sample (those with 1.4 GHz radio luminosities in the range 10^{24} to 10^{25} W/Hz, corresponding to…
We report the discovery of large-scale diffuse radio emission from what appears to be a large-scale filamentary network of galaxies in the region of cluster ZwCl 2341.1+0000, and stretching over an area of at least $6 h^{-1}_{50}$ Mpc in diameter. Multicolour CCD observations yield photometric redshifts indicating that a significant fraction of the optical galaxies in this region is at a redshift of z=0.3. This is supported by spectroscopic measurements of 4 galaxies in the SDSS survey at a mean z=0.27. We present VLA images at 20 cm (NVSS) and 90 cm wavelengths, showing the detailed radio str…
