- ID:
- ivo://nasa.heasarc/mcg
- Title:
- Morphological Galaxy Catalog
- Short Name:
- MCG
- Date:
- 02 May 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The MCG database contains the "Morphological Catalogue of Galaxies," a compilation of information for approximately 34,000 galaxies found and examined on the Palomar Observatory Sky Survey (POSS). Individual identifiers are assigned for about 29,000 galaxies and information on the remaining 5,000 is present in the extensive notes of the published catalogs (Vorontsov-Velyaminov et al. 1962-1968). The catalog is structured according to the POSS zones and is numbered from +15 (corresponding to +90 deg) to +01 (+06 deg zone) and +00 (equatorial zone) to -05 (-30 deg zone); the fields are numbered with increasing right ascension. The original goal of the compilation was to be complete for galaxies brighter than magnitude 15.1, but the final catalog lists many objects considerably fainter. Information given in the original printed volumes includes: cross- identifications to the NGC (Dreyer 1888) and IC (Dreyer 1895, 1908) catalogs, equatorial coordinates for 1950.0, magnitude, estimated sizes and intensities of the bright inner region and the entire object, estimated inclination, and coded description (by symbols) of the appearance of the galaxy. Each field is then followed by notes on individual objects. All of the above data except the coded description are included in the machine version, except that special coding (e.g. for uncertainty or source designation) is not present (other than for the NGC/IC cross identifications [added at the Astronomical Data Center for this machine version]). Although the notes are not computerized, the presence of a note in the original is flagged in the machine version Detailed descriptions of modifications, corrections and the record format are provided for the machine-readable version of the "Morphological Catalogue of Galaxies" (Vorontsov-Velyaminov et al. 1962-68); see the Additional Information section below. In addition to hundreds of individual corrections, a detailed comparison of the machine-readable with the published catalog resulted in the addition of 116 missing objects, the deletion of 10 duplicate records, and a format modification to increase storage efficiency. This is a service provided by NASA HEASARC .
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- ID:
- ivo://nasa.heasarc/noras
- Title:
- Northern ROSAT All-Sky (NORAS) Galaxy Cluster Survey Catalog
- Short Name:
- NORASGalClus
- Date:
- 02 May 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- In the construction of an X-ray-selected sample of galaxy clusters for cosmological studies, the authors have assembled a sample of 495 X-ray sources which were found to show extended X-ray emission in the first processing of the ROSAT All-Sky Survey (RASS I), the Northern ROSAT All-Sky (NORAS) Galaxy Cluster Survey Catalog. The sample covers the celestial region with declination >=0 degrees and Galactic latitude |b| >= 20 degrees, and comprises sources with a Position Sensitive Proportional Counter (PSPC) count rate >= 0.06 counts/s and a source extent likelihood of L >= 7. In an optical follow-up identification program, the authors found 378 (76%) of these sources to be clusters of galaxies. It was necessary to reanalyze the sources in this sample with a new X-ray source characterization technique to provide more precise values for the X-ray flux and source extent than obtained from the standard processing. This new method, termed growth curve analysis (GCA), has the advantage over previous methods in its ability to be robust, to be easy to model and to integrate into simulations, to provide diagnostic plots for visual inspection, and to make extensive use of the X-ray data. The source parameters obtained assist the source identification and provide more precise X-ray fluxes. This reanalysis is based on data from the more recent second processing of the ROSAT Survey, RASS II. The authors present a catalog of the cluster sources with the X-ray properties obtained as well as a list of the previously flagged extended sources that are found to have a non-cluster counterpart. In their paper, they discuss the process of source identification from the combination of optical and X-ray data. To investigate the overall completeness of the cluster sample as a function of the X-ray flux limit, they extended the search for X-ray cluster sources to the RASS II data for the northern sky region between 9 and 14 hours in right ascension. They included the search for X-ray emission from known galaxy clusters as well as a new investigation of extended X-ray sources. In the course of this search, they found X-ray emission from 85 additional Abell clusters and 56 very probable cluster candidates among the newly found extended sources. A comparison of the X-ray cluster number counts of the NORAS sample with the ROSAT-ESO Flux-limited X-ray (REFLEX) Cluster Survey results leads to an estimate of the completeness of the NORAS sample of ROSAT All-Sky Survey (RASS) I extended clusters of about 50% at an X-ray flux of FX(0.1-2.4 keV) = 3 x 10-12 ergs s<sup>-1</sup> cm<sup>-2</sup>. The estimated completeness achieved by adding the supplementary sample in the study area amounts to about 82% in comparison to REFLEX. The low completeness introduces an uncertainty in the use of the sample for cosmological statistical studies that will be cured with the completion of the continuing Northern ROSAT All-Sky (NORAS) Cluster Survey project. This table was created by the HEASARC in June 2005 based on CDS table J/ApJS/129/435, table1.dat through table9.dat inclusive. 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:
- 02 May 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 .
- ID:
- ivo://nasa.heasarc/pgc2003
- Title:
- Principal Galaxy Catalog (PGC) 2003
- Short Name:
- PGC
- Date:
- 02 May 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The Principal Galaxy Catalog, 2003 Version (PGC2003) is a new catalog of principal galaxies. It constitutes the framework of the HYPERLEDA database that supersedes the LEDA one, with more data and more capabilities. The catalog is still restricted to confirmed galaxies, i.e. about one million galaxies, brighter than a B-magnitude of ~18. In order to provide the best possible identification for each galaxy, the authors give accurate coordinates (typical accuracy of better than 2 arcseconds), diameters, axis ratios and position angles. Diameters and axis ratios have been homogenized to the RC2 system at the limiting surface brightness of 25 B-mag/arcsec<sup>2</sup>, using a new method (EPIDEMIC). In order to provide the best designation for each galaxy, the authors have collected names from 50 catalogs. The compatibility of the spelling has been tested against NED and SIMBAD, and, as far as possible a spelling is used that is compatible with both. For some cases, where no consensus exists between NED, SIMBAD and LEDA, the authors have proposed some changes that could make the spelling of names fully compatible. The full catalog is distributed through the CDS and can be extracted from HYPERLEDA, <a href="http://leda.univ-lyon1.fr/">http://leda.univ-lyon1.fr/</a>. This table was created by the HEASARC in July 2004 based on the <a href="https://cdsarc.cds.unistra.fr/ftp/cats/VII/237">CDS catalog VII/237</a> file pgc.dat.gz. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/romabzcat
- Title:
- Roma-BZCAT Multi-Frequency Catalog of Blazars
- Short Name:
- ROMABZCAT
- Date:
- 02 May 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains the 5th edition of the Roma-BZCAT catalog of blazars which contains coordinates and multi-frequency data of 3561 sources. It presents several relevant changes with respect to the past editions which are briefly described in the reference paper. The Roma-BZCAT catalog contains data on 3561 sources, about 30% more than in the 1st edition, which either confirmed blazars or exhibiting characteristics close to this type of sources. With respect to the previous editions, this new edition has relevant changes in the sources' classification. The authors emphasize that all the sources in the Roma-BZCAT have a detection in the radio band. Moreover, complete spectroscopic information is published and could be accessed by the authors for all of them, with the exception of BL Lac candidates. Consequently, peculiar sources such as the so called "radio quiet BL Lacs", which are reported in some other catalogs, are not included here because of possible contamination by hot stars and other extragalactic objects. In the 5th edition, the authors use a similar denomination for the blazars to that adopted in the previous editions. Each blazar is identified by a code, with 5BZ for all blazars, a fourth letter that specifies the type (B, G, Q or U), followed by the truncated equatorial coordinates (J2000). The authors introduced the edition number before the letters BZ to avoid possible confusion due to the fact that several sources changed their old names because of a newly adopted classification. The 5th edition contains 1151 BZB sources (92 of which are reported as candidates because their optical spectra could not be found in the literature), 1909 BZQ sources, 274 BZG sources, and 227 BZU objects. This database table was originally ingested by the HEASARC in September 2013, based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/495/691">CDS Catalog J/A+A/495/691</a> file bzcat4.dat. It was updated in March 2016, and it is now based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/VII/274">CDS Catalog VII/274</a> file bzcat5.dat. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/rassdssagn
- Title:
- ROSAT All-Sky Survey and SDSS DR5 Sample of X-Ray Emitting AGN
- Short Name:
- RASS/SDSSAGN
- Date:
- 02 May 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains further results of a program aimed at yielding ~ 10<sup>4</sup> fully characterized optical identifications of ROSAT X-ray sources. The program employs X-ray data from the ROSAT All Sky Survey (RASS) and both optical imaging and spectroscopic data from the Sloan Digital Sky Survey (SDSS). RASS/SDSS data from 5740 deg<sup>2</sup> of sky spectroscopically covered in SDSS Data Release 5 (DR5) provide an expanded catalog of 7000 confirmed quasars and other active galactic nuclei (AGN) that are probable RASS identifications. Again, in this expanded catalog the identifications as X-ray sources are statistically secure, with only a few percent of the SDSS AGNs likely to be randomly superposed on unrelated RASS X-ray sources. Most identifications continue to be quasars and Seyfert 1 galaxies with 15 < m < 21 and 0.01 < z < 4, but the total sample size has grown to include very substantial numbers of even quite rare AGN, e.g., it now includes several hundreds of candidate X-ray-emitting BL Lac objects and narrow-line Seyfert 1 galaxies. In addition to exploring rare subpopulations, such a large total sample may be useful when considering correlations between the X-ray and the optical and may also serve as a resource list from which to select the ``best'' object (e.g., the X-ray-brightest AGN of a certain subclass at a preferred redshift or luminosity) for follow-up X-ray spectral or alternate detailed studies. 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 in February 2007 based on the combination of the electronic versions of tables 1 through 6 from the above reference which were obtained from the electronic AJ website. It replaces a previous version containing the results presented by Anderson et al. (2003, AJ, 126, 2209) which were based on a cross-correlation of the RASS with optical data from very early on in the SDSS program, e.g., extending back to the 'Early Data Release' before SDSS photometric calibrations were complete. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/rasssdssgc
- Title:
- ROSAT All-Sky Survey and Sloan Digital Sky Survey DR7 Galaxy Clusters
- Short Name:
- RASSSDSSGC
- Date:
- 02 May 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The authors use ROSAT All-Sky Survey (RASS) broad-band X-ray images and the optical clusters identified from the Sloan Digital Sky Survey Data Release 7 (SDSS DR7) to estimate the X-ray luminosities around ~65,000 candidate galaxy clusters with masses >~10<sup>13</sup> h<sup>-1</sup> M<sub>sun</sub> based on an optical to X-ray (OTX) code that they developed. They obtain a catalog with X-ray luminosities for all 64,646 clusters. A total of 34,522 (~53%) of these clusters have a signal-to-noise ratio S/N > 0 after subtracting the background signal. According to the reference paper (but see HEASARC Caveats section below), this catalog contains 817 clusters (473 at redshift z <= 0.12) with S/N > 3 for their X-ray detections (an additional 12,629 clusters have 3 >= S/N > 1 and 21,076 clusters have 1 >= S/N > 0). The authors find about 65% of these X-ray clusters have their most massive member located near the X-ray flux peak; for the remaining 35%, the most massive galaxy is separated from the X-ray peak, with the separation following a distribution expected from a Navarro-Frenk-White profile. In the reference paper, the authors investigate a number of correlations between the optical and X-ray properties of these X-ray clusters, and find that the cluster X-ray luminosity is correlated with the stellar mass (luminosity) of the clusters, as well as with the stellar mass (luminosity) of the central galaxy and the mass of the halo, although the scatter in these correlations is large. Comparing the properties of X-ray clusters of similar halo masses but having different X-ray luminosities, they find that massive haloes with masses >~10<sup>14</sup> h<sup>-1</sup> M<sub>sun</sub> contain a larger fraction of red satellite galaxies when they are brighter in X-ray. An opposite trend is found in central galaxies in relative low-mass haloes with masses <~10<sup>14</sup> h<sup>-1</sup> M<sub>sun</sub> where X-ray brighter clusters have smaller fraction of red central galaxies. Clusters with masses >~10<sup>14</sup> h<sup>-1</sup> M<sub>sun</sub> that are strong X-ray emitters contain many more low-mass satellite galaxies than weak X-ray emitters. These results are also confirmed by checking X-ray clusters of similar X-ray luminosities but having different characteristic stellar masses. The cluster catalog containing the optical properties of member galaxies and the X-ray luminosity is also available at <a href="http://gax.shao.ac.cn/data/Group.html">http://gax.shao.ac.cn/data/Group.html</a>. The optical data used in this analysis are taken from the SDSS galaxy group catalogs of Yang et al. (2007, ApJ, 671, 153), constructed using the adaptive halo-based group finder of Yang et al. (2005, MNRAS, 356, 1293), here updated to DR7. The parent galaxy catalog is the New York University Value-Added Galaxy Catalog (NYU-VAGC; Blanton et al. 2005, AJ, 129, 2562) based on the SDSS DR7 (Abazajian et al. 2009, ApJS, 182, 543), which contains an independent set of significantly improved reductions. In this study, the authors adopt a Lambda cold dark matter cosmology whose parameters are consistent with the 7-year data release of the WMAP mission: Omega<sub>m</sub> = 0.275, Omega<sub>Lambda</sub> = 0.725, h = H<sub>0</sub>/(100 km s<sup>-1</sup> Mpc<sup>-1</sup>) = 0.702, and sigma<sub>8</sub> = 0.816. This table was created by the HEASARC in June 2017 based upon the <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/MNRAS/439/611">CDS Catalog J/MNRAS/439/611</a> file catalog.dat. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/rassbscpgc
- Title:
- ROSAT All-Sky Survey Bright Source Catalog/Catalog of Principal Galaxies Matches
- Short Name:
- RASSBSCPGC
- Date:
- 02 May 2025
- 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 .
- ID:
- ivo://nasa.heasarc/rasscals
- Title:
- ROSAT All-Sky Survey CALS Galaxy Groups Catalog
- Short Name:
- RASS-CALS
- Date:
- 02 May 2025
- 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:
- 02 May 2025
- 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 .
