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11. ROSAT North Ecliptic Pole Survey Active Galactic Nuclei Catalog
ID:
ivo://nasa.heasarc/rosnepagn
Title:
ROSAT North Ecliptic Pole Survey Active Galactic Nuclei Catalog
Short Name:
ROSATNEPAGN
Date:
07 Mar 2025
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; <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJS/149/29">CDS Cat. <J/ApJS/149/29></a>). 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 .
12. ROSAT Radio-Loud Quasars Catalog
ID:
ivo://nasa.heasarc/rosatrlq
Title:
ROSAT Radio-Loud Quasars Catalog
Short Name:
ROSAT/RLQ
Date:
07 Mar 2025
Publisher:
NASA/GSFC HEASARC
Description:
Brinkmann et al. (1997) have compiled a sample of all quasars with measured radio emission from the Veron-Cetty - Veron catalog (1993, VERON93, CDS/ADC Cat. VII/166) detected by ROSAT (i) in the ALL-SKY SURVEY (RASS, Voges 1992, in Proc. of the ISY Conference `Space Science', ESA ISY-3, ESA Publications, p.9, ADC/<a href="https://cdsarc.cds.unistra.fr/ftp/cats/IX/10">CDS Cat. IX/10</a>), (ii) as targets of pointed observations, or (iii) as serendipitous sources from pointed observations, as publicly available from the ROSAT point source catalog (ROSAT-SRC, Voges et al. 1995, ADC/<a href="https://cdsarc.cds.unistra.fr/ftp/cats/IX/11">CDS Cat. IX/11</a>). The total number of ROSAT detected radio quasars from the above three sources is 654 objects. 69 of the objects are classified as radio-quiet using the defining line at a radio-loudness of 1.0, and 10 objects have no classification. The 5GHz data are from the 87GB radio survey, the NED database, or from the Veron-Cetty - Veron catalog. The power law indices and their errors are estimated from the two hardness ratios given by the SASS assuming Galactic absorption. The X-ray flux densities in the ROSAT band (0.1-2.4keV) are calculated from the count rates using the energy to counts conversion factor for power law spectra and Galactic absorption. For the photon index, the authors used the value obtained for a individual source if the estimated 1 sigma error was smaller than 0.5, otherwise they used the mean value of 2.14. This database was created by the HEASARC in January 1999, based on CDS/ADC Catalog J/A+A/319/413. This is a service provided by NASA HEASARC .
13. ROSAT Radio-Quiet Quasars Catalog
ID:
ivo://nasa.heasarc/rosatrqq
Title:
ROSAT Radio-Quiet Quasars Catalog
Short Name:
ROSAT/RQQ
Date:
07 Mar 2025
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/<a href="https://cdsarc.cds.unistra.fr/ftp/cats/VII/166">CDS Cat. VII/166</a>) 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/<a href="https://cdsarc.cds.unistra.fr/ftp/cats/IX/10">CDS Cat. IX/10</a>), 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/<a href="https://cdsarc.cds.unistra.fr/ftp/cats/IX/11">CDS Cat. IX/11</a>), 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/<a href="https://cdsarc.cds.unistra.fr/ftp/cats/IX/10">CDS Cat. IX/10</a>). 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 .
15. Sloan Digital Sky Survey (DR5)/XMM-Newton Quasar Survey Catalog
ID:
ivo://nasa.heasarc/sdssxmmqso
Title:
Sloan Digital Sky Survey (DR5)/XMM-Newton Quasar Survey Catalog
Short Name:
SDSSXMMQSO
Date:
07 Mar 2025
Publisher:
NASA/GSFC HEASARC
Description:
This table contains the 5th Data Release Sloan Digital Sky Survey (DR5 SDSS)/XMM-Newton Quasar Survey Catalog. This catalog contains 792 SDSS DR5 quasars with optical spectra that have been observed serendipitously in the X-rays with XMM-Newton. These quasars cover a redshift range of z = 0.11 - 5.41 and a magnitude range of i = 15.3 - 20.7. Substantial numbers of radio-loud (70) and broad absorption line (51) quasars exist within this sample. Significant X-ray detections at >=2 sigma account for 87% of the sample (685 quasars), and 473 quasars are detected at >=6 sigma, sufficient to allow X-ray spectral fits. For detected sources, ~60% have X-ray fluxes between F(2-10 keV) = (1-10) x 10<sup>-14</sup> erg cm<sup>-2</sup> s<sup>-1</sup>. The authors fit a single power law, a fixed power law with intrinsic absorption left free to vary, and an absorbed power-law model to all quasars with X-ray signal-to-noise ratio >= 6, resulting in a weighted mean photon index Gamma = 1.91 +/- 0.08, with an intrinsic dispersion sigma(Gamma) = 0.38. For the 55 sources (11.6%) that prefer intrinsic absorption, the authors find a weighted mean N<sub>H</sub> = 1.5 +/- 0.3 x 10<sup>21</sup> cm<sup>-2</sup>. They find that Gamma correlates significantly with optical color, Delta(g-i), the optical-to-X-ray spectral index (alpha<sub>ox</sub>), and the X-ray luminosity. While the first two correlations can be explained as artifacts of undetected intrinsic absorption, the correlation between Gamma and X-ray luminosity appears to be a real physical correlation, indicating a pivot in the X-ray slope. This table was created by the HEASARC in July 2009 based on electronic versions of Tables 1 and 2 from the paper which were obtained from the Astrophysical Journal web site. This is a service provided by NASA HEASARC .
16. Sloan Digital Sky Survey NBC Quasar Candidate Catalog
ID:
ivo://nasa.heasarc/sdssnbcqsc
Title:
Sloan Digital Sky Survey NBC Quasar Candidate Catalog
Short Name:
SDSSQSOCand.
Date:
07 Mar 2025
Publisher:
NASA/GSFC HEASARC
Description:
The Nonparametric Bayes Classifier (NBC) Quasar Candidate Catalog is a catalog of 100,563 unresolved, UV-excess (UVX) quasar candidates with magnitudes to as faint as 21 in the g-band from 2099 square degrees of the Sloan Digital Sky Survey (SDSS) Data Release One (DR1) imaging data. Existing spectra of 22,737 sources reveals that 22,191 (97.6%) are quasars; accounting for the magnitude dependence of this efficiency, the authors estimate that 95,502 (95.0%) of the objects in the catalog are quasars. Such a high efficiency is unprecedented in broadband surveys of quasars. This "proof-of-concept" sample is designed to be maximally efficient, but still has 94.7% completeness to unresolved, g ~< 19.5, UVX quasars from the DR1 quasar catalog. This efficient and complete selection is the result of the application of a probability density type analysis to training sets that describe the four-dimensional color distribution of stars and spectroscopically confirmed quasars in the SDSS. Specifically, the authors use a nonparametric Bayesian classification, based on kernel density estimation, to parametrize the color distribution of astronomical sources - allowing for fast and robust classification. They further supplement the catalog by providing photometric redshifts and matches to FIRST/VLA, ROSAT, and USNO-B sources. 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 database table was created by the HEASARC in August 2005 based on CDS table J/ApJS/155/257/table1.dat. This is a service provided by NASA HEASARC .
17. Swift BAT 60-Month Survey of Active Galactic Nuclei Catalog
ID:
ivo://nasa.heasarc/swbatagn60
Title:
Swift BAT 60-Month Survey of Active Galactic Nuclei Catalog
Short Name:
SWBATAGN60
Date:
07 Mar 2025
Publisher:
NASA/GSFC HEASARC
Description:
Surveys above 10 keV represent one of the best resources to provide an unbiased census of the population of active galactic nuclei (AGNs). The authors present the results of 60 months of observation from 2005 March to 2010 March of the hard X-ray sky with the Swift Burst Alert Telescope (BAT). In this time frame, BAT detected (in the 15 - 55 keV band) 720 sources with a signal-to-noise ratio of >= 5 sigma in an all-sky survey, of which 428 are associated with AGNs, most of which are nearby. This sample has negligible incompleteness and statistics which are a factor of ~ 2 larger over similarly complete sets of AGNs. The sample contains (at least) 15 bona fide Compton-thick AGNs and 3 likely candidates. Compton-thick AGNs represent ~ 5% of AGN samples detected above 15 keV. The authors use the BAT data set to refine the determination of the log N - log S of AGNs which is extremely important, now that NuSTAR prepares for launch, toward assessing the AGN contribution to the cosmic X-ray background. The authors show that the log N - log S of AGNs selected above 10 keV is now established to ~ 10% precision. They derive the luminosity function of Compton-thick AGNs and measure a space density of 7.9 (+4.1, -2.9) x 10<sup>-5</sup> Mpc<sup>-3</sup> for objects with a de-absorbed luminosity larger than 2 x 10<sup>42</sup> erg s<sup>-1</sup>. As the BAT AGNs are all mostly local, they allow us to investigate the spatial distribution of AGNs in the nearby universe regardless of absorption. The authors find concentrations of AGNs that coincide spatially with the largest congregations of matter in the local (<= 85 Mpc) universe. There is some evidence that the fraction of Seyfert 2 objects is larger than average in the direction of these dense regions. This table was created by the HEASARC in May 2012, based on an electronic version of Table 1 from the referenced paper, which was obtained from the ApJ website. This is a service provided by NASA HEASARC .
18. Tartarus: Reduced ASCA AGN Data (Version 3.1)
ID:
ivo://nasa.heasarc/tartarus
Title:
Tartarus: Reduced ASCA AGN Data (Version 3.1)
Short Name:
ASCA/AGN
Date:
07 Mar 2025
Publisher:
NASA/GSFC HEASARC
Description:
The Tartarus database contains the results of a detailed but systematic analysis of ASCA observations of active galactic nuclei (AGN). It contains source and background events files, spectra, ancillary response files and response matrices, images, and assorted light curves for a large number of ASCA AGN observations. Spectral fit results are done by automatic XSPEC fitting. This database table allows easy access to reduced AGN data for the whole community, allowing the maximum scientific return from the data. Availability of publishable light curves, images, and spectra (which can also be readily re-fitted) should be particularly valuable to astronomers with little direct experience in the reduction of X-ray data. Version 3.1 has been created by analyzing all ASCA observing sequences with targets designated as AGN, as indicated by a leading "7" in the ASCA observing sequence number. Version 3.1 contains products for all 611 observing sequences designated as AGN observations. This is a significant improvement over Versions 1 and 2. Moreover, the 611 sequences for which products are available are complete in the sense that either the target object was not detected (in which case an upper limit on GIS2 source counts is given) or the intended AGN target was detected and the data were fully analyzed. In order to obtain the most accurate background subtraction and minimize contamination from any nearby sources, version 3.1 makes more use of custom extraction regions than previous versions. It is expected that version 3.1 will be replaced when the final ASCA calibration is completed. This database table has been created by the Tartarus Team, and they, rather than Imperial College London or the HEASARC, are responsible for the contents. It was ingested by the HEASARC in August, 2005. This is a service provided by NASA HEASARC .
19. The VSOP (the VLBI Space Observatory Programme) 5 GHz AGN (Active Galactic Nuclei) Survey Program Analysis Data
ID:
ivo://jvo/isas/darts/halca/halca_vsop_survey_program_data
Title:
The VSOP (the VLBI Space Observatory Programme) 5 GHz AGN (Active Galactic Nuclei) Survey Program Analysis Data
Short Name:
HALCA_AGN
Date:
19 Oct 2021 06:40:34
Publisher:
JVO
Description:
A significant fraction of the mission time of VSOP was to be dedicated to the VSOP Survey Programme of bright compact Active Galactic Nuclei (AGN) at 5 GHz, which was lead by ISAS. The VSOP Survey Sources are an unbiased dataset of 294 targets, of which 82% were successfully observed.
20. UV-Bright Quasar Survey (UVQS) DR1 Catalog
ID:
ivo://nasa.heasarc/uvqs
Title:
UV-Bright Quasar Survey (UVQS) DR1 Catalog
Short Name:
UVQS
Date:
07 Mar 2025
Publisher:
NASA/GSFC HEASARC
Description:
This table contains data from the first data release (DR1) from the UV-bright Quasar Survey (UVQS) for new z ~ 1 active galactic nuclei (AGN) across the sky. Using simple GALEX UV and WISE near-IR color selection criteria, the authors generated a list of 1,450 primary candidates with FUV < 18.5 mag, that is contained in the HEASARC table (entries with source_sample = 'P'). They obtained discovery spectra, primarily on 3m-class telescopes, for 1,040 of these candidates and confirmed 86% as AGN, with redshifts generally at z > 0.5. Including a small set of observed secondary candidates, the authors report the discovery of 217 AGN with GALEX FUV magnitudes < 18 mag that previously had no reported spectroscopic redshifts. These are excellent potential targets for UV spectroscopy before the end of the Hubble Space Telescope mission. The main data products of UVQS are publicly available through the Mikulski Archive for Space Telescopes (MAST). The authors have performed an all-sky survey for z ~ 1, FUV-bright quasars selected from GALEX and WISE photometry. In several of the observing runs, conditions were unexpectedly favorable and we exhausted the primary candidates at certain right ascension ranges. To fill the remaining observing time, they generated a secondary candidate list. This secondary set of 2,010 candidates is also contained in this HEASARC table (entries with source_sample = 'S'). The authors proceeded to obtain discovery-quality long-slit spectra (i.e., low-dispersion, large-wavelength coverage, modest signal-to-noise ratio (S/N) of their UV-bright Quasar Survey (UVQS) candidates in one calendar year. The principal facilities were: (i) the dual Kast spectrometer on the 3m Shane telescope at the Lick Observatory; (ii) the Boller & Chivens (BCS) spectrometer on the Irenee du Pont 100-inch telescope at the Las Campanas Observatory; and (iii) the Calar Alto Faint Object Spectrograph on the CAHA 2.2-meter telescope at the Calar Alto Observatory (CAHA). They acquired an additional ~20 spectra on larger aperture telescopes (Keck/ESI, MMT/MBC, Magellan/MagE) during twilight or under poor observing conditions. Typical exposure times were limited to < ~200s, with adjustments for fainter sources or sub-optimal observing conditions. Table 3 in the reference paper provides a list of the details of the observations of these candidates. From the total candidates list of 3,460 objects, the authors measured high-quality redshifts (redshift quality flag values of 3 or greater) for 1,121 sources. They assumed that every source with a recessional velocity v<sub>r</sub> = z * c < 500 km s<sup>-1</sup> was "Galactic", which they associate with the Galaxy and members of the Local Group. This included sources where the eigenspectra fits were poor yet a low v<sub>r</sub> was indisputable (e.g., stars). Many of these were assigned z = 0 exactly. The remainder of the UVQS sources were assumed to be extragalactic AGN, and the derived redshift information for these sources (which was given in Table 4 of the reference paper) has been incorporated into this HEASARC representation of UVQS. Finally, there were 93 sources with good-quality spectra for which we cannot the authors could not recover a secure redshift. The majority of these have been previously cataloged as blazars (or BL Lac objects). Table 6 in the reference paper lists the sample of these unknown or insecure redshift objects. This table was created by the HEASARC in April 2017 based upon the <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/AJ/152/25">CDS Catalog J/AJ/152/25</a> files table1.dat, table2.dat, and table4.dat. This is a service provided by NASA HEASARC .