- ID:
- ivo://nasa.heasarc/rassbscpgc
- Title:
- ROSAT All-Sky Survey Bright Source Catalog/Catalog of Principal Galaxies Matches
- Short Name:
- RASSBSCPGC
- Date:
- 10 May 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- In a correlation study of the ROSAT All-Sky Survey Bright Source Catalog (RASS-BSC, <a href="https://cdsarc.cds.unistra.fr/ftp/cats/XI/10">CDS Cat. <XI/10></a>, the HEASARC table RASSBSC) with the Catalogue of Principal Galaxies (PGC, <a href="https://cdsarc.cds.unistra.fr/ftp/cats/VII/119">CDS Cat. <VII/119></a>, the HEASARC table PGC2003), 904 X-ray sources were found that possess possible extragalactic counterparts within a search radius of 100 arcseconds. A visual screening process was applied to classify the reliability of the correlations. 547 correlations have been quoted as reliable identifications. From these, 349 sources are known to be active galaxies. Although for the other sources no hints for activity were found in the literature, 69% of those for which we have distances show X-ray luminosities exceeding those of normal galaxies, a clear sign that these galaxies also own hitherto unreported X-ray active components. Some objects are located inside or in the direction of a known group or cluster of galaxies. Their X-ray flux may therefore be in part affected by hot gas emission. In the paper, luminosity and log N-log S distributions are used to characterize different subsamples. Nuclei that are both optically and X-ray active are found predominantly in spirals. Two special source samples are defined, one with candidates for X-ray emission from hitherto unknown groups or clusters of galaxies, and one with high X-ray luminosity sources, that are likely candidates to possess hitherto unreported active galactic nuclei. Besides a compilation of X-ray and optical parameters, X-ray overlays on optical images for all the objects are also supplied as part of this work. This table contains 1124 optical galaxy entries for the 904 relevant X-ray candidates/counterparts from the RASS. Besides a compilation of X-ray and optical parameters for each source, the results of an identification screening are also given. The 904 optical images with X-ray overlay contours (xID_nnn.ps.gz) used in the screening process are added for each user's own judgement of the reliability of the associations. This table was created by the HEASARC in March 2012 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/378/30">CDS catalog J/A+A/378/30</a> file table1.dat, the list of PGC galaxies identified as possible counterparts to RASS Bright Source Catalog X-ray sources. This is a service provided by NASA HEASARC .
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- ID:
- ivo://nasa.heasarc/rasscals
- Title:
- ROSAT All-Sky Survey CALS Galaxy Groups Catalog
- Short Name:
- RASS-CALS
- Date:
- 10 May 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains the catalog from the ROSAT All-Sky Survey (RASS) Center for Astrophysics (CfA) Loose Systems, or RASSCALS, the largest X-ray and optical survey of low-mass galaxy groups as of its publication date in 2000. The authors drew 260 groups from the combined Center for Astrophysics and Southern Sky Redshift Surveys, covering one-quarter of the sky to a limiting Zwicky magnitude of m<sub>z</sub> = 15.5. They detected 61 groups (23%) as extended X-ray sources. The X-ray detections have a median membership of nine galaxies, a median recession velocity cz = 7250 km/s, a median projected velocity dispersion sigma(p) = 400 km/s, and a median X-ray luminosity L(x) = 3 x 10<sup>42</sup> /h(100)<sup>2</sup> erg/s, where the Hubble constant is H(0) = 100 h(100) km/s/Mpc. The data in this table replace the preliminary analysis of the X-ray data which was presented in Mahdavi et al., 1999, ApJ, 518, 69 (CDS Cat. <J/ApJ/518/69>. This table was created by the HEASARC in September 2005 based on CDS tables J/ApJ/534/114/table2.dat & table3.dat. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/rass6dfgs
- Title:
- ROSAT All-Sky Survey/6dF Galaxy Survey Catalog of X-Ray Selected AGN
- Short Name:
- RASS6DFGS
- Date:
- 10 May 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains a catalog of 3405 X-ray sources from the ROSAT All Sky Survey (RASS) Bright Source Catalog which fall within the area covered by the 6dF Galaxy Survey (6dFGS). The catalog is count-rate limited at 0.05 ct s<sup>-1</sup> in the X-ray and covers the area of sky with Declination < 0 degrees and |b| > 10 degrees. The RASS-6dFGS sample was one of the additional target catalogs of the 6dFGS and as a result the authors obtained optical spectra for 2224 (65 per cent) RASS sources. Of these, 1715 (77%) have reliable redshifts with a median redshift of z = 0.16 (excluding the Galactic sources). For the optically bright sources (b_J <= 17.5) in the observed sample, over 90% have reliable redshifts. The catalog mainly comprises quasi-stellar objects (QSOs) and active galaxies but also includes 238 Galactic sources. Of the sources with reliable redshifts, the majority are type 1 active galactic nuclei (AGN, 69%), while 12% are type 2 AGN, 6% absorption-line galaxies and 13% are stars. The authors also identify a small number of optically faint, very low redshift, compact objects which fall outside the general trend in the b_J - z plane. The RASS-6dFGS catalog complements a number of Northern hemisphere samples, particularly the ROSAT Bright Source Catalogue-NRAO VLA Sky Survey (RBSC-NVSS) sample (Bauer et al. 2000, ApJS, 129, 547), and furthermore, in the same region of sky (-40 degrees < Declination < 0 degrees) reveals an additional 561 sources that were not identified as part of that sample. The authors detect 918 sources (27%) of the RASS-6dFGS sample in the radio using either the 1.4 GHz NVSS or the 843 MHz Sydney University Molonglo Sky Survey (SUMSS) catalogues and find that the detection rate changes with redshift. At redshifts larger than 1 virtually all of these sources have radio counterparts and with a median flux density of 1.15 Jy, they are much stronger than the median flux density of 28.6 mJy for the full sample. The authors attribute this to the fact that the X-ray flux of these objects is being boosted by a jet component, possibly Doppler boosted, that is only present in radio-loud AGN. The RASS-6dFGS sample provides a large set of homogeneous optical spectra ideal for future studies of X-ray emitting AGN. This table was created by the HEASARC in April 2010 based on an electronic version of Table 3 from the reference paper obtained from the MNRAS web site. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/rassebcs
- Title:
- ROSAT All-Sky Survey Extended Brightest Cluster Sample
- Short Name:
- RASSBCS
- Date:
- 10 May 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains the ROSAT All-Sky Survey (RASS) Brightest Cluster Sample (BCS) and the Low-Flux Extension, which together form the Extended BCS (eBCS). The main BCS, which was presented in Ebeling et al. (1998, MNRAS, 301, 881; Paper I), is a 90% flux-complete sample of the 201 X-ray-brightest clusters of galaxies in the northern hemisphere (Dec >=0 degrees), at high Galactic latitudes (|b| >= 20 degrees), with measured redshifts z <= 0.3 and X-ray fluxes higher than 4.4 x 10<sup>-12</sup> erg/cm<sup>2</sup>/s in the 0.1 - 2.4 keV band. This sample, called the ROSAT Brightest Cluster Sample, is selected from RASS data and is the largest X-ray-selected cluster sample compiled to the publication date (1998). In addition to Abell clusters which form the bulk of the sample, the BCS also contains the X-ray-brightest Zwicky clusters and other clusters selected from their X-ray properties alone. Effort has been made to ensure the highest possible completeness of the sample and the smallest possible contamination by non-cluster X-ray sources. X-ray fluxes were computed using an algorithm tailored for the detection and characterization of X-ray emission from galaxy clusters. These fluxes are accurate to better than 15% (mean 1-sigma error). The low-flux extension of the X-ray-selected ROSAT Brightest Cluster Sample was published in Ebeling et al. (2000, MNRAS, 318, 333; Paper IV). Like the original BCS and employing an identical selection procedure, the BCS extension is compiled from ROSAT All-Sky Survey (RASS) data in the northern hemisphere (Dec >=0 degrees) and at high Galactic latitudes (|b| >= 20 degrees). It comprises 99 X-ray-selected clusters of galaxies with measured redshifts z <= 0.3 (as well as eight more at z > 0.3) and total fluxes between 2.8 x 10<sup>-12</sup> and 4.4 x 10<sup>-12</sup> erg/cm<sup>2</sup>/s in the 0.1 - 2.4keV band (the latter value being the flux limit of the original BCS). The extension can be combined (as it has been in this HEASARC table) with the main sample published in 1998 to form the homogeneously selected extended BCS (eBCS), the largest and statistically best understood cluster sample to emerge from the RASS to date. The nominal completeness of the combined sample (defined with respect to a power-law fit to the bright end of the BCS log N -log S distribution) is relatively low at 75% (compared with 90% for the high-flux sample of Paper I). However, just as for the original BCS, this incompleteness can be accurately quantified, and thus statistically corrected for, as a function of X-ray luminosity and redshift. In addition to its importance for improved statistical studies of the properties of clusters in the local Universe, the low-flux extension of the BCS is also intended to serve as a finding list for X-ray-bright clusters in the northern hemisphere which the authors hoped will prove useful in the preparation of cluster observations to be made with the next generation of X-ray telescopes such as Chandra and XMM-Newton. This table was created by the HEASARC in August 2005 based on the merger of 2 CDS tables, J/MNRAS/301/881/table3.dat.gz (the main sample) and J/MNRAS/318/333/table1.dat.gz (the low-flux extension). This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/reflex
- Title:
- ROSAT-ESO Flux-Limited X-Ray (REFLEX) Galaxy Cluster Survey
- Short Name:
- ROSAT/ESOClus.
- Date:
- 10 May 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table is the ROSAT-ESO Flux-Limited X-Ray (REFLEX) Galaxy Cluster Survey Catalog. The REFLEX Cluster Survey provides information on the X-ray properties, redshifts, and some identification details of clusters in the REFLEX sample. The catalog describes a statistically complete X-ray flux-limited sample of 447 galaxy clusters above an X-ray flux of 3 x 10<sup>-12</sup> erg/s/cm<sup>2</sup> (0.1 to 2.4 keV) in an area of 4.24 steradians in the southern sky. The cluster candidates were first selected by their X-ray emission in the ROSAT-All Sky Survey and subsequently spectroscopically identified in the frame of an ESO key program. Previously described tests have shown that the sample is more than 90% complete and there is a conservative upper limit of 9% on the fraction of clusters with a dominant X-ray contamination from AGN. This data set is at present the largest, statistically complete X-ray galaxy cluster sample. The sample forms the basis of several cosmological studies, one of the most important applications being the assessment of the statistics of the large-scale structure of the universe and the test of cosmological models. The X-ray luminosities and other distance-dependent cluster parameters are calculated for a Lambda cosmology with a Hubble Constant H<sub>0</sub> of 70 km/s/Mpc, Omega<sub>M</sub> of 0.3, and Omega<sub>Lambda</sub> of 0.7. The CDS version of this catalog contains an additional table (reflex50.dat) with these parameters calculated for an Einstein-de Sitter universe with H<sub>0</sub> = 50 km/s/Mpc, Omega<sub>M</sub> = 1.0, and Omega<sub>Lambda</sub> = 0.0. This table was created by the HEASARC in October 2004 based on CDS tables J/A+A/425/367/reflex70.dat and J/A+A/425/367/reflex.dat. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/rosnepagn
- Title:
- ROSAT North Ecliptic Pole Survey Active Galactic Nuclei Catalog
- Short Name:
- ROSATNEPAGN
- Date:
- 10 May 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The ROSAT North Ecliptic Pole (NEP) Survey of Active Galactic Nuclei (AGN) Catalog is an X-ray flux-limited sample of 219 AGN discovered in the contiguous 80.7 square degrees region of the ROSAT North Ecliptic Pole (NEP) Survey (Gioia et al. 2003, ApJS, 149, 29; CDS Cat. <J/ApJS/149/29>). This catalog features complete optical identifications and spectroscopic redshifts. The median redshift, X-ray flux, and X-ray luminosity are z = 0.41, fx = 1.1 x 10<sup>-13</sup> erg/cm<sup>2</sup>/s, and Lx = 9.2 x 10<sup>43</sup> h70<sup>-2</sup> erg/s (0.5 - 2.0 keV), respectively. Unobscured Type 1 AGN are the dominant constituents (90%) of this soft X-ray-selected sample of AGN. This catalog sample includes several notable revisions relative to previous versions of the catalog (Mullis 2001, Ph. D. thesis, U. Hawaii; Gioia et al. 2003, ApJS, 149, 29, available in HEASARC Browse as the ROSNEPOID table). Firstly, the AGN fluxes and luminosities previously reported were overestimated by approximately 20% on average as a result of an error in the conversion of X-ray count rate to flux. Secondly, the sample has grown by 1 because of the reclassification of one of the X-ray sources (RX J1824.7+6509). Finally, in the present study the authors have adopted the presently favored "concordance" cosmology in computing the X-ray luminosities. The revised and updated catalog with corrected properties presented here should be the reference point for any future work with the ROSAT NEP AGN sample. This table was created by the HEASARC in August 2005 based on CDS table J/ApJ/617/192/table1.dat. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/rosgalclus
- Title:
- ROSAT PSPC Catalog of Clusters of Galaxies
- Short Name:
- ROSAT/Clust.
- Date:
- 10 May 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This is a catalog of 203 clusters of galaxies serendipitously detected in 647 ROSAT PSPC high Galactic latitude pointings covering 158 square degrees. This is one of the largest X-ray-selected cluster samples, comparable in size only to the ROSAT All-Sky Survey sample of nearby clusters (Ebeling et al. 1997). Clusters in the inner 17.'5 of the ROSAT PSPC field of view are detected using the spatial extent of their X-ray emission. Fluxes of detected clusters range from 1.6 x 10^-14 to 8 x 10^-12 ergs s^-1 cm^-2 in the 0.5-2 keV energy band. X-ray luminosities range from 10^42 ergs s^-1, corresponding to very poor groups, to ~5 x 10^44 ergs s^-1, corresponding to rich clusters. The cluster redshifts range from z = 0.015 to z > 0.5. The catalog lists X-ray fluxes, core radii, and spectroscopic redshifts for 73 clusters and photometric redshifts for the remainder. Of 223 X-ray sources, 203 have been optically confirmed as clusters of galaxies. Of the remaining 20 sources, 19 are likely false detections arising from blends of unresolved point X-ray sources. Optical identifications of the remaining object are hampered by a nearby bright star. Above a flux of 2 x 10^-13 ergs s^-1 cm^-2, 98% of extended X-ray sources are optically confirmed clusters. The number of false detections and their flux distribution are in perfect agreement with simulations. The log N-log S relation for clusters derived from this catalog shows excellent agreement with counts of bright clusters derived from the Einstein Extended Medium Sensitivity Survey and the ROSAT All-Sky Survey. At fainter fluxes, its log N-log S relation agrees with the smaller area WARPS survey. The cluster counts appear to be systematically higher than those from a 50 square degree survey by Rosati et al. This database was created by the HEASARC in December 2001 based on the CDS/ADC catalog J/ApJ/502/558/ (table3.dat). This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/rosatrqq
- Title:
- ROSAT Radio-Quiet Quasars Catalog
- Short Name:
- ROSAT/RQQ
- Date:
- 10 May 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- A sample of all radio-quiet quasars or quasars without radio detection taken from the Veron-Cetty - Veron catalog (1993, VERON93, ADC/CDS Cat. VII/166) which were either (i) detected by ROSAT in the ALL-SKY SURVEY (RASS, Voges 1992, in Proc. of the ISY Conference `Space Science', ESA ISY-3, ESA Publications, p.9, ADC/CDS Cat. IX/10), or (ii) detected as targets of pointed observations, or (iii) detected as serendipitous sources in pointed observations that were publicly available in the ROSAT point source catalog (ROSATSRC, Voges et al. 1995, ADC/CDS Cat. IX/11), has been compiled by Yuan et al. (1998, A&A, 330, 108). For all sources, they used the results of the Standard Analysis Software System (SASS, Voges et al. 1992, in Proc. of the ISY Conference `Space Science', ESA ISY-3, ESA Publications, p.223), employing the most recent processing for the Survey data (RASS-II, Voges et al. 1996, ADC/CDS Cat. IX/10). The total number of quasars in this ROSAT Radio-Quiet Quasars Catalog is 846. Sixty-nine of the radio-quiet objects with radio detections have already been presented in a previous paper (Brinkmann, Yuan, and Siebert 1997, Cat. J/A+A/319/413) using the RASS-I results. Seventeen objects were found to be radio-loud from recent radio surveys and were marked in the table. When available, the power law photon indices and the corresponding absorption column densities (NH) were estimated from the two hardness ratios given by the SASS, both with free fitted NH and for Galactic absorption. The unabsorbed X-ray flux densities in the ROSAT band (0.1-2.4keV) were calculated from the count rates using the energy to counts conversion factor for power law spectra and Galactic absorption. The authors used as the photon index the value obtained for the individual source if the estimated 1-{sigma} error was smaller than 0.5, otherwise they used the redshift-dependent mean value (see the paper for details). Notice that the positions of sources in this catalog are not the positions of the X-ray sources, but the optical positions of the quasars as given in the VERON93 Catalog (Wolfgang Brinkmann, 1998 private communication). This database was created by the HEASARC in December 1998, based on CDS/ADC Catalog J/A+A/330/108. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/roxa
- Title:
- ROXA (Radio-Optical-X-ray at ASDC) Blazars Catalog
- Short Name:
- ROXA
- Date:
- 10 May 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- 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. In preparation for these missions it is necessary to identify new samples of blazars to study their multi-frequency characteristics and statistical properties. The authors have compiled a sample of objects with blazar-like properties via a cross-correlation between large radio (NVSS, ATCAPMN) and X-ray surveys (RASS) using the SDSS-DR4 and 2dF survey data to spectroscopically identify their candidates and test the validity of the selection method. They present the Radio-Optical-X-ray catalog built at ASDC (ROXA), a list of 816 objects among which 510 are confirmed blazars. Only 19% of the candidates turned out to be certainly non-blazars, demonstrating the high efficiency of our selection method. This catalog includes 173 new blazar identifications, or about 10% of all presently known blazars. The relatively high flux threshold in the X-ray energy band (given by the RASS survey) preferentially selects objects with high F_X/F_r ratio, leading to the discovery of new High Energy Peaked BL Lac (HBLs). This catalog therefore includes many new potential targets for GeV-TeV observations. The selection method consisted of three steps: 1) a first cross-correlation between radio and X-ray surveys (the NRAO VLA Sky Survey, ATCAPMN (ATCA catalogue of compact PMN sources) and ROSAT All Sky Survey; 2) for each radio/X-ray match, optical magnitudes were retrieved from the Guide Star Catalog; 3) for all radio/optical/X-ray matches the authors calculated the X-ray to optical (alpha_ox) and radio to optical (alpha_ro) spectral slopes and took only sources with alpha_ox and alpha_ro values within the blazar area. For each object, redshift, B and G magnitudes, radio fluxes at 1.4 GHz and at 5 GHz, X-ray flux, F_X/F_r ratio, X-ray luminosity, radio luminosity, Ca H&K break and classification are given. This table was created by the HEASARC in November 2007 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/472/699">CDS catalog J/A+A/472/699</a> file catalog.dat. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/sdssnbckde
- Title:
- SDSS NBCKDE Catalog of Photometrically Selected Quasar Candidates
- Short Name:
- SDSSNBCKDE
- Date:
- 10 May 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains a catalog of 1,015,082 quasar candidates selected from the photometric imaging data of the Sloan Digital Sky Survey (SDSS) using a non-parametric Bayesian classification kernel density estimator (NBC-KDE). It excludes 157,075 initial candidates that were culled as known or likely contaminants. The objects are all point sources to a limiting magnitude of i = 21.3 from 8417 deg<sup>2</sup> of imaging from SDSS Data Release 6 (DR6). This sample extends the previous catalog (Paper I: Richards et al. 2004, ApJS, 155, 257) by using the latest SDSS public release data and probing both ultraviolet (UV)-excess and high-redshift quasars. While the addition of high-redshift candidates reduces the overall efficiency (quasars:quasar candidates) of the catalog to ~80%, it is expected to contain no fewer than 850,000 bona fide quasars, which is ~8 times the number of the previous sample and ~10 times the size of the largest spectroscopic quasar catalog. Cross-matching between this photometric catalog and spectroscopic quasar catalogs from both the SDSS and 2dF survey yields 88,879 spectroscopically confirmed quasars. For judicious selection of the most robust UV-excess sources (~500,000 objects in all), the efficiency is nearly 97 - more than sufficient for detailed statistical analyses. The catalog's completeness to type 1 (broad-line) quasars is expected to be no worse than 70%, with most missing objects occurring at z < 0.7 and 2.5 < z < 3.0. In addition to classification information, the authors provide photometric redshift estimates (typically good to Delta(z) +/- 0.3 [2-sigma]) and cross-matching with radio, X-ray, and proper-motion catalogs. Finally, the authors have considered the catalog's utility for determining the optical luminosity function of quasars and are able to confirm the flattening of the bright-end slope of the quasar luminosity function at z ~ 4 as compared to z ~ 2. Much more information on the SDSS is available at the project's web site at <a href="http://www.sdss.org/">http://www.sdss.org/</a>. This table was created by the HEASARC based on an electronic version of Table 1 in the reference paper which was obtained from the ApJ web site. This is a service provided by NASA HEASARC .