- ID:
- ivo://nasa.heasarc/arxa
- Title:
- Atlas of Radio/X-Ray Associations (ARXA)
- Short Name:
- ARXA
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The Atlas of Radio/X-Ray Associations (ARXA) is a compendium of all cataloged or APM/USNO-A optical objects which are found to be associated with XMM-Newton, Chandra, RASS, HRI, PSPC or WGACAT X-ray detections, or with NVSS, FIRST or SUMSS radio detections. All detections are listed, plus double radio lobes where found. The source number counts are: <pre> Optical objects - 602,570. NVSS - 266,148 core associations, plus 8309 double lobes. FIRST - 173,383 core associations, plus 12,844 double lobes. SUMSS - 59,138 core associations, plus 2529 double lobes. XMM associations - 57,778. Chandra associations - 32,951. ROSAT RASS - 47,486. ROSAT HRI - 15,523. ROSAT PSPC - 35,607. WGA - 24,226. </pre> Each optical object is given as one entry in this catalog, containing the sky coordinates, the object name (from the literature where available), APM and USNO-A sourced red and blue photometry, redshift, the source catalogs for the name and redshift, the calculated odds that the object is a quasar, galaxy, star, or erroneous association, and the radio & X-ray identifiers, up to 10 of them possible although usually just 1 or 2. This catalog supersedes the previous similar compilation by the same author, the Quasars.org (QORG) Catalog, called QORGCAT in the HEASARC's Browse (see <a href="http://quasars.org/qorg-data.htm">http://quasars.org/qorg-data.htm</a>). Questions or comments on ARXA may be directed to eric@flesch.org. See also: <pre> APM home page <a href="http://www.ast.cam.ac.uk/~apmcat">http://www.ast.cam.ac.uk/~apmcat</a> USNO-A home page <a href="http://www.nofs.navy.mil/">http://www.nofs.navy.mil/</a> NVSS home page <a href="http://www.cv.nrao.edu/nvss/">http://www.cv.nrao.edu/nvss/</a> FIRST home page <a href="http://sundog.stsci.edu/">http://sundog.stsci.edu/</a> SUMSS home page <a href="http://www.astrop.physics.usyd.edu.au/SUMSS/index.html">http://www.astrop.physics.usyd.edu.au/SUMSS/index.html</a> XMM-Newton home page <a href="http://xmmssc-www.star.le.ac.uk">http://xmmssc-www.star.le.ac.uk</a> HRI & PSPC home page <a href="http://www.mpe.mpg.de/ROSAT/">http://www.mpe.mpg.de/ROSAT/</a> WGA home page <a href="http://wgacat.gsfc.nasa.gov/wgacat/wgacat.html">http://wgacat.gsfc.nasa.gov/wgacat/wgacat.html</a> RASS-FSC home page <a href="http://www.xray.mpe.mpg.de/rosat/survey/rass-fsc">http://www.xray.mpe.mpg.de/rosat/survey/rass-fsc</a> RASS-BSC home page <a href="http://www.xray.mpe.mpg.de/rosat/survey/rass-bsc">http://www.xray.mpe.mpg.de/rosat/survey/rass-bsc</a> Chandra home page <a href="http://chandra.harvard.edu">http://chandra.harvard.edu</a> XAssist home page <a href="http://xassist.pha.jhu.edu/zope/xassist">http://xassist.pha.jhu.edu/zope/xassist</a> (XMMX & CXOX sources are from XAssist) </pre> If using this catalog in published research, please add a small mention in the acknowledgements. This table is based on research which made use of the NASA/IPAC Extragalactic Database (NED) operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA. This online catalog was created by the HEASARC in January 2010 based on a machine-readable table obtained from the author's ARXA web site at <a href="http://quasars.org/arxa.htm">http://quasars.org/arxa.htm</a>. This is a service provided by NASA HEASARC .
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- ID:
- ivo://nasa.heasarc/cfa2s
- Title:
- CfA Redshift Survey: South Galactic Cap Data
- Short Name:
- CfARed.S.
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The Center for Astrophysics (CfA) Redshift Survey South Galactic Cap (CFA2S) Catalog contains redshifts for a sample of about 4300 galaxies with blue (Zwicky B(0) type) magnitude <= 15.5 covering the range from 20 h to 4h in right ascension and from -2.5 deg to 90 deg in declination. This sample is complete for all galaxies in the merge of the Zwicky et al. and Nilson catalogs in the south Galactic cap. Redshifts for 2964 of these were measured as part of the second CfA Redshift Survey. The data reveal large voids in the foreground and background of the Perseus-Pisces Supercluster. The largest of these voids lies at a mean velocity ~ 8000km/s, has diameter of ~ 5000km/s, and is enclosed by a complex of dense structures. The large structure known as the Perseus-Pisces Supercluster forms the near side of this complex. On the far side of this large void, at a mean velocity of ~ 12000km/s, there is another coherent dense wall. The structures in this survey support the view that galaxies generally lie on surfaces surrounding or nearly surrounding low-density regions or voids. This table was created by the HEASARC in March 2005 based on CDS table J/ApJS/121/287/cfa2s.dat.gz This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/cosmosvlba
- Title:
- COSMOS Field VLBA Observations 1.4-GHz Source Catalog
- Short Name:
- COSMOSVLBA
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains the results of a project using wide-field Very Long Baseline Interferometry (VLBI) observations at 1.4 GHz of 2,865 known radio sources in the Cosmic Evolution Survey (COSMOS) field, a field which has exceptional multi-wavelength coverage. The main objective of this study is to identify the active galactic nuclei (AGN) in this field. Wide-field VLBI observations were made of all known radio sources in the COSMOS field at 1.4 GHz using the Very Long Baseline Array (VLBA). The authors also collected complementary multiwavelength information from the literature for the VLBA-detected sources.The combination of the number of sources, sensitivity, angular resolution and the area covered by this project are unprecedented. A catalog which contains the VLBI-detected sources is presented, the main purpose of which is to be used as an AGN catalog. the complementary multiwavelength (optical, infrared and X-ray) information of the VLBI-detected sources is also presented. The authors have detected 468 radio sources, expected to be AGN, with the VLBA. This is, to date, the largest sample assembled of VLBI-detected sources in the sub-mJy regime. They find a detection fraction of 20% +/- 1%, considering only those sources from the input catalog which were in principle detectable with the VLBA (2,361). As a function of the VLA flux density, the detection fraction is higher for higher flux densities, since at high flux densities a source could be detected even if the VLBI core accounts for a small percentage of the total flux density. As a function of redshift, the authors see no evolution of the detection fraction over the redshift range 0.5 < z < 3. In addition, they find that faint radio sources typically have a greater fraction of their radio luminosity in a compact core: ~70% of the sub-mJy sources detected with the VLBA have more than half of their total radio luminosity in a VLBI-scale component, whereas this is true for only ~30% of the sources that are brighter than 10 mJy. This suggests that fainter radio sources differ intrinsically from brighter ones. Across the entire sample, the authors find the predominant morphological classification of the host galaxies of the VLBA-detected sources to be early type (57%), although this varies with redshift and at z > 1.5 they find that spiral galaxies become the most prevalent (48%). The number of detections is high enough to study the faint radio population with statistically significant numbers. The authors demonstrate that wide-field VLBI observations, together with new calibration methods such as multi-source self-calibration and mosaicking, result in information which is difficult or impossible to obtain otherwise. This table contains 504 entries, including the 468 VLBA-detected sources and, for sources with multiple components, entries for the individual components. Among the detected sources, there are 452 single, 13 double, 2 triple and 1 quadruple source. Source entries have no suffix in their vlba_source_id, e.g., 'C3293', whereas component entries have a, b, c or d suffixes, e.g., 'C0090a' (and a value of 2 for the multi_cpt_flag parameter). This table was created by the HEASARC in December 2017 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/607/A132">CDS Catalog J/A+A/607/A132</a> files vlba_cat.dat and vlba_mw.dat. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/twodfqsoz
- Title:
- 2dF QSO Redshift (2QZ) Survey
- Short Name:
- TWODFQSOZ
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The final catalog of the 2dF QSO Redshift Survey (2QZ) is based on Anglo-Australian Telescope 2dF spectroscopic observations of 44,576 color-selected (u, b<sub>J</sub>, r) objects with 18.25 < b<sub>J</sub> < 20.85 selected from automated plate measurement scans of UK Schmidt Telescope (UKST) photographic plates. The 2QZ comprises 23,338 quasi-stellar objects (QSOs), 12,292 galactic stars (including 2,071 white dwarfs) and 4,558 compact narrow emission-line galaxies. The authors obtained a reliable spectroscopic identification for 86 per cent of objects observed with 2dF. They also report on the 6dF QSO Redshift Survey (6QZ), based on UKST 6dF observations of 1,564 brighter (16 < b<sub>J</sub> < 18.25) sources selected from the same photographic input catalog. In total, the authors identified 322 QSOs spectroscopically in the 6QZ. The completed 2QZ is, by more than a factor of 50, the largest homogeneous QSO catalog ever constructed at these faint limits (b<sub>J</sub> < 20.85) and high QSO surface densities (35 QSOs/deg<sup>2</sup>). As such, it represents an important resource in the study of the Universe at moderate-to-high redshifts. The survey area comprised 30 UKST fields, arranged in two 75 degrees by 5 degrees declination strips, one passing across the South Galactic Gap centered on Dec = -30 degrees (the SGP strip), and the other across the North Galactic Gap centered on Dec = 0 degrees (referred to in the reference paper as the equatorial strip, but also known as the NGP strip. The total survey area is 721.6 deg<sup>2</sup>, when allowance is made for regions of sky excised around bright stars. Spectroscopic observations of the input catalogue were made with the 2dF instrument at the Anglo-Australian Telescope (AAT; the 2QZ sample) and the 6dF instrument at the UKST (the 6QZ sample). 2dF spectroscopic observations began in January 1997 and were completed in April 2002. Six-degree Field observations were performed over the period 2001 March-2002 September. This online catalog was created by the HEASARC in October 2010 based on the machine-readable table 2qz.dat obtained from the CDS (their catalog VII/241). This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/gcscat
- Title:
- Globular Cluster Systems of Galaxies Catalog
- Short Name:
- GCSCAT
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains a catalog of 422 galaxies with published measurements of their globular cluster (GC) populations. Of these, 248 are E galaxies, 93 are S0 galaxies, and 81 are spirals or irregulars. Among various correlations of the total number of GCs with other global galaxy properties, the authors find that the number of globular clusters N<sub>GC</sub> correlates well though nonlinearly with the dynamical mass of the galaxy bulge M<sub>dyn</sub> = 4 sigma _e_<sup>2</sup> R<sub>e</sub>/G, where sigma<sub>e</sub> is the central velocity dispersion and R<sub>e</sub> the effective radius of the galaxy light profile. In their paper, the authors also present updated versions of the GC specific frequency S<sub>N</sub> and specific mass S<sub>M</sub> versus host galaxy luminosity and baryonic mass. These graphs exhibit the previously known U-shape: highest S<sub>N</sub> or S<sub>M</sub> values occur for either dwarfs or supergiants, but in the mid-range of galaxy size (10<sup>9</sup> - 10<sup>10</sup> L<sub>sun</sub>) the GC numbers fall along a well-defined baseline value of S<sub>N</sub> ~= 1 or S<sub>M</sub> = 0.1, similar among all galaxy types. Along with other recent discussions, the authors suggest that this trend may represent the effects of feedback, which systematically inhibited early star formation at either very low or very high galaxy mass, but which had its minimum effect for intermediate masses. Their results strongly reinforce recent proposals that GC formation efficiency appears to be most nearly proportional to the galaxy halo mass M<sub>halo</sub>. The mean "absolute" efficiency ratio for GC formation that the authors derive from the catalog data is M<sub>GCS</sub>/M<sub>halo</sub> = 6 x 10<sup>-5</sup>. They suggest that the galaxy-to-galaxy scatter around this mean value may arise in part because of differences in the relative timing of GC formation versus field-star formation. Finally, they find that an excellent empirical predictor of total GC population for galaxies of all luminosities is N<sub>GC</sub> ~ (R<sub>e</sub> sigma<sub>e</sub>)<sup>1.3</sup>, a result consistent with fundamental plane scaling relations. This table was created by the HEASARC in February 2014 based on an electronic version of Table 1 from the reference paper which was obtained from the ApJ web site. A duplicate entry for NGC 4417 was removed in June 2019. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/lqac
- Title:
- Large Quasar Astrometric Catalog, 3rd Release
- Short Name:
- LQAC
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- Since the release of the original Large Quasar Astrometric Catalog (LQAC: Souchay et al. 2009, A&A, 494, 815), a large number of quasars have been discovered through very dense observational surveys. Following the same procedure as in the first release of the LQAC, the authors aim is to compile all the quasars recorded up until the present date, with the best determination of their ICRS equatorial coordinates, i.e., with respect to the newly established ICRF2 (the second realization of the International Celestial Reference Frame) and with the maximum of information concerning their physical properties, e.g., redshifts, photometry, absolute magnitudes. In the second paper, the authors first of all made a substantial review of the definitions and properties of quasars and AGN (Active Galactic Nuclei), the differentiation of these objects being unclear in the literature and even for specialists. This served their purpose when deciding which kinds of objects would be taken into account in this compilation. Then, they carried out the cross-identification between the 9 catalogs of quasars chosen for their accuracy and their huge number of objects, using a flag for each of them, and including all the available data related to magnitudes (infrared and optical), radio fluxes and redshifts. They also performed cross identification with external catalogs 2MASS, B1.0 and GSC2.3 in order to complete photometric data for the objects. Moreover, they computed the absolute magnitude of their extragalactic objects by taking into account recent studies concerning Galactic absorption. In addition, substantial improvements were brought with respect to the first release of the LQAC. First, an LQAC name was given for each object based on its equatorial coordinates with respect to the ICRS, following a procedure which creates no ambiguity for identification. Secondly, the equatorial coordinates of the objects were recomputed more accurately according to the algorithms used for the elaboration of the Large Quasar Reference Frame (LQRF) (Andrei et al., 2009, <a href="https://cdsarc.cds.unistra.fr/ftp/cats/I/313">CDS Cat. I/313</a>). Thirdly, the authors introduced a morphological classification for the objects which enabled them in particular to define clearly if the object is point-like or extended. The authors adopted a cosmology with H<sub>0</sub> = 70 km s<sup>-1</sup> Mpc<sup>-1</sup>, Omega<sub>M</sub> = 0.3, Omega<sub>Lambda</sub> = 0.7, and q<sub>0</sub> = -0.65 in LQAC-3 (which is slightly different from that adopted for LQAC-2, notice). The final catalog, called LQAC-2, contained 187,504 quasars. This was roughly 65% larger than the 113,666 quasars recorded in the first version of the LQAC (Souchay et al. 2009, <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/494/799">CDS Cat. J/A+A/494/799</a>) and a little more than the number of quasars recorded in the up-dated version of the Veron-Cetty and Veron (2010, <a href="https://cdsarc.cds.unistra.fr/ftp/cats/VII/258">CDS Cat. VII/258</a>, HEASARC VERONCAT table) catalog, which was the densest compilation of quasars up to the present one. In addition to the quantitative and qualitative improvements implemented in this compilation, the authors discussed the homogeneity of the data and carried out a statistical analysis concerning the spatial density and the distance to the nearest neighbor in their published paper. The authors adopted a cosmology with H<sub>0</sub> = 72 km s<sup>-1</sup> Mpc<sup>-1</sup> and q<sub>0</sub> = -0.58 in this study. From an astrometric point of view, quasars constitute quasi-ideal reference objects in the celestial sphere, with an a priori absence of proper motion. Since the second release of the LQAC, a large number of quasars have been discovered, in particular with the upcoming new release of the SDSS quasars catalog. Following the same procedure as in the two previous releases of the LQAC, The authors' aim for LQAC-3 was to compile all the quasars recorded until the present date, with accurate recomputation of their equatorial coordinates in the ICRS and with the maximum of information concerning their physical properties, such as the redshift, the photometry, and the absolute magnitudes. The authors carried out the cross-identification between the 9 catalogs of quasars chosen for their huge number of objects, including all the available data related to magnitudes, radio fluxes, and redshifts. This cross identification was particularly delicate because of a slight change in coordinates between the objects common to two successive releases of the SDSS and the elimination of some of them. Equatorial coordinates were recomputed more accurately according to the algorithms used for the elaboration of the Large Quasar Reference Frame (LQRF). Moreover, absolute magnitudes and morphological indexes of the new objects were given, following the same method as in the LQAC-2. The final catalog, called LQAC-3, contains 321,957 objects including a small proportion of AGNs (14,128) and BL Lac objects (1,183). This is roughly 70% more than the number of objects recorded in the LQAC-2. The LQAC-3 will be useful for the astronomical community since it gives the most complete information available about the whole set of already recorded quasars, with emphasis on the precision and accuracy of their coordinates with respect to the ICRF2. This table was created by the HEASARC in June 2016 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/583/A75">CDS Catalog J/A+A/583/A75</a>, file lqac3.dat. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/lcrscat
- Title:
- Las Campanas Redshift Survey Catalog
- Short Name:
- LCRSCAT
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The Las Campanas Redshift Survey (LCRS) consists of 26,418 redshifts of galaxies selected from a CCD-based catalog obtained in the R band. The survey covers over 700 deg<sup>2</sup> in six strips, each 1.5 x 80 degrees, three each in the north and south Galactic caps. The median redshift in the survey is about 30,000 km s<sup>-1</sup>. Essential features of the galaxy selection and redshift measurement methods are described and tabulated in the reference paper. These details are important for subsequent analysis of the LCRS data. Two-dimensional representations of the redshift distributions reveal many repetitions of voids, on the scale of about 5000 km s<sup>-1</sup>, sharply bounded by large walls of galaxies as seen in nearby surveys. Statistical investigations of the mean galaxy properties and of clustering on the large scale are reported elsewhere. These include studies of the luminosity function, power spectrum in two and three dimensions, correlation function, pairwise velocity distribution, identification of large-scale structures, and a group catalog. This table contains entries for 94959 objects from the LCRS for which photometric data were obtained and which were initially classified as galaxies on the basis of this photometric information, although subsequent spectroscopy indicated that a small fracton of them are actually stars. There are 27021 objects out of this total which have spectroscopic redshift information (either of themselves or of a nearby object). See also the LCRS home pages at: <a href="http://qold.astro.utoronto.ca/~lin/lcrs.html">http://qold.astro.utoronto.ca/~lin/lcrs.html</a>. This table was created by the HEASARC in May 2010 based on the electronic version of Table 3 from the above reference which was obtained from the <a href="https://cdsarc.cds.unistra.fr/ftp/cats/VII/203">CDS Catalog VII/203</a> file catalog.dat. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/twomassrsc
- Title:
- 2MASS Redshift Survey (2MRS) Catalog
- Short Name:
- TWOMASSRSC
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table is based on the results of the 2MASS Redshift Survey (2MRS), a ten-year project to map the full three-dimensional distribution of galaxies in the nearby universe. The Two Micron All Sky Survey (2MASS) was completed in 2003 and its final data products, including an extended source catalog (XSC), are available online. The 2MASS XSC contains nearly a million galaxies with K<sub>s</sub> <= 13.5 mag and is essentially complete and mostly unaffected by interstellar extinction and stellar confusion down to a galactic latitude of |b| = 5 degrees for bright galaxies. Near-infrared wavelengths are sensitive to the old stellar populations that dominate galaxy masses, making 2MASS an excellent starting point to study the distribution of matter in the nearby universe. The authors selected a sample of 44,599 2MASS galaxies with K<sub>s</sub> <= 11.75 mag and |b| >= 5 degrees (>= 8 degrees toward the Galactic bulge) as the input catalog for their survey. They obtained spectroscopic observations for 11,000 galaxies and used previously obtained velocities for the remainder of the sample to generate a redshift catalog that is 97.6% complete to well-defined limits and covers 91% of the sky. This provides an unprecedented census of galaxy (baryonic mass) concentrations within 300 Mpc. Earlier versions of their survey have been used in a number of publications that have studied the bulk motion of the Local Group, mapped the density and peculiar velocity fields out to 50 h<sup>-1</sup> Mpc, detected galaxy groups, and estimated the values of several cosmological parameters. Additionally, the authors present morphological types for a nearly complete sub-sample of 20,860 galaxies with K<sub>s</sub> <= 11.25 mag and |b| >= 10 degrees. The authors initially selected 45,086 sources which met the following criteria: <pre> K<sub>s</sub> <= 11.75 mag and detected at H, E(B - V) <= 1 mag, |b| >= 5 degrees for 30 degrees < l < 330 degrees, |b| >= 8 degrees otherwise. </pre> They rejected 324 sources of galactic origin (multiple stars, planetary nebulae, and H II regions) or pieces of galaxies detected as separate sources by the 2MASS pipeline. Additionally, they flagged 314 bona fide galaxies with compromised photometry for reprocessing at a future date. Some of these galaxies have bright stars very close to their nuclei which were not detected by the pipeline. Others are in regions of high stellar density and their center positions and/or isophotal radii have been incorrectly measured by the pipeline. Lastly, some are close pairs or multiples but the pipeline only identified a single object. A detailed explanation of the steps taken to reject and reprocess the flagged galaxies is given in the Appendix of the reference paper. In summary, the final input catalog contained here has 44,599 entries (plotted using black symbols in Figure 1 of the reference paper). In this table, redshifts for 43,533 of the selected galaxies, or 97.6% of the sample, are presented. This table was created by the HEASARC in April 2012 based on an electronic version of Table 3 of the reference paper which was obtained from the ApJS website. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/milliquas
- Title:
- Million Quasars Catalog (MILLIQUAS), Version 8 (2 August 2023)
- Short Name:
- MILLIQUAS
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains the Million Quasars (MILLIQUAS) Catalog, Version 8 (2 August 2023). It is a compendium of 907,144 type-I QSOs and AGN, largely complete from the literature to 30 June 2023. 66,026 QSO candidates are also included, calculated via radio/X-ray association (including double radio lobes) as being 99% likely to be quasars. Blazars and type-II objects are also included, bringing the total count to 1,021,800. 60.7% of all objects show Gaia-EDR3 astrometry. Low-confidence/quality or questionable objects (so deemed by their researchers) are not included in Milliquas. Additional quality cuts can be applied as detailed in the HMQ paper (Flesch 2015,PASA,32,10). Full QSO/AGN classification is accomplished via spectral lines, yielding a reliable spectroscopic redshift. Two spectral lines are required, or one spectral line refining a compatible photometric redshift. Obscured AGN with redshifts from the hosts only are taken to be type-II objects. Some legacy quasars with neither good spectra nor radio/X-ray association were flagged by Gaia-EDR3 as 5-sigma moving (i.e., stars), and so were removed from Milliquas. All objects are de-duplicated across source catalogs. The author's aim here is to present one unique reliable object per each data row. Two NIQs offset < 2 arcsec can be reported as a single object if within the same host. Lenses are reported as single objects onto the brightest quasar imaged. (Milliquas is not a catalog of lenses.) The contents are relatively simple; each object is shown as one entry with the sky coordinates (of whatever epoch), its original name, object class, red and blue optical magnitudes, PSF class, redshift, the citations for the name and redshift, and up to four radio/X-ray identifiers where applicable. Questions/comments/praise/complaints may be directed to Eric Flesch at eric@flesch.org. If you use this catalog in published research, the author requests that you please cite it. The confirmed quasars of this catalog (to Jan 2015) were published as the Half Million Quasars (HMQ) catalog: Flesch E., 2015,PASA,32,10. Note however that Milliquas uses optical sky data from ASP (2017,PASA,34,25) whereas the HMQ used optical sky data from QORG (2004,A&A,427,387) Appendix A. This table was updated by the HEASARC in July 2023 based on a machine-readable catalog obtained from the author's MILLIQUAS website at <a href="https://quasars.org/milliquas.htm">https://quasars.org/milliquas.htm</a>. <p> This research has made use of the NASA/IPAC Extragalactic Database (NED) which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. <p> This research has made use of the SIMBAD database and CDS cross-match service (to obtain Gaia-EDR3 and Pan-STARRS photometry) provided by CDS, Strasbourg, France. <a href="https://simbad.cds.unistra.fr/simbad">https://simbad.cds.unistra.fr/simbad</a> This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/osrilqxray
- Title:
- Optically Selected Radio-Intermediate and Loud Quasars X-ray Emission Catalog
- Short Name:
- OSRILQXRAY
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This catalog contains some of the results of an investigation into the X-ray properties of radio-intermediate and radio-loud quasars (RIQs and RLQs, respectively). The authors have combined large, modern optical (e.g., SDSS) and radio (e.g., FIRST) surveys with archival X-ray data from Chandra, XMM-Newton, and ROSAT to generate an optically selected sample that includes 188 RIQs and 603 RLQs. This sample is constructed independently of X-ray properties but has a high X-ray detection rate (85%); it provides broad and dense coverage of the luminosity-redshift (l-z) plane, including at high redshifts (22% of the objects have z = 2-5), and it extends to high radio-loudness R<sub>L</sub> values (33% of objects have R<sub>L</sub> = log(L<sub>r</sub>/L<sub>o</sub>) = 3 - 5), where L<sub>r</sub> and L<sub>o</sub> are the rest-frame monochromatic luminosities at 5 GHz and 2500 Angstroms, respectively). The authors measure the "excess" X-ray luminosity of RIQs and RLQs relative to radio-quiet quasars (RQQs) as a function of radio loudness and luminosity, and parametrize the X-ray luminosity of RIQs and RLQs both as a function of optical/UV luminosity and also as a joint function of optical/UV and radio luminosity. RIQs are only modestly X-ray bright relative to RQQs; it is only at high values of radio loudness (R<sub>L</sub> >~ 3.5) and radio luminosity that RLQs become strongly X-ray bright. This HEASARC table contains the primary sample from the reference paper. The authors consider three categories of quasars in this work: RQQs, RIQs, and RLQs (rather than just RQQs and RLQs), where the define RIQs to consist of objects with 1 <= R<sub>L</sub> < 2; consequently, the objects they classify as RLQs satisfy R<sub>L</sub> >= 2. The primary sample contained herein consists of 654 optically selected RIQs and RLQs with SDSS/FIRST observations and high-quality X-ray coverage from Chandra (171), XMM-Newton (202), or ROSAT (281). The primary sample is split nearly evenly between spectroscopic (312) and high-confidence photometric (342) quasars. Most (562) of the primary sample objects possess serendipitous off-axis X-ray coverage, while the remainder (92) were targeted in the observations used in this sample. The X-ray detection fraction for the primary sample is 84%; the detection fraction for those objects with Chandra/XMM-Newton/ROSAT coverage is 95%/92%/70% (typical ROSAT observations are comparatively less sensitive and have higher background). The authors adopt a standard cosmology with H<sub>0</sub> = 70 km s<sup>-1</sup> Mpc<sup>-1</sup>, Omega<sub>M</sub> = 0.3, and Omega<sub>Lambda</sub> = 0.7 throughout their study. This table was created by the HEASARC in October 2012 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJ/726/20">CDS Catalog J/ApJ/726/20</a> file table1.dat. This is a service provided by NASA HEASARC .
