Subject: survey source / Publisher: NASA/GSFC HEASARC / Facility: SDSS

Start Over Subject survey source Publisher NASA/GSFC HEASARC Facility SDSS

1. CHAMP/SDSS Nearby Low-Luminosity AGN Catalog

ID:: ivo://nasa.heasarc/champsdssa
Title:: CHAMP/SDSS Nearby Low-Luminosity AGN Catalog
Short Name:: CHAMPSDSSA
Date:: 07 Mar 2025
Publisher:: NASA/GSFC HEASARC
Description:: The combination of the Sloan Digital Sky Survey (SDSS) and the Chandra Multiwavelength Project (ChaMP; Green et al. 2004, ApJS, 150, 43) currently offers the largest and most homogeneously selected sample of nearby galaxies for investigating the relations between X-ray nuclear emission, nebular line emission, black hole masses, and the properties of the associated stellar populations. The authors provide X-ray spectral fits and valid uncertainties for all the galaxies with counts ranging from 2 to 1325 (mean 76, median 19). They present in their paper novel constraints that both X-ray luminosity LX and X-ray spectral energy distribution bring to the galaxy evolutionary sequence HII -> Seyfert/Transition Object -> LINER -> Passive suggested by optical data. In particular, the authors show that both LX and Gamma, the slope of the power law that best fits the 0.5 - 8 keV spectra, are consistent with a clear decline in the accretion power along the sequence, corresponding to a softening of their spectra. This implies that, at z ~ 0, or at low-luminosity active galactic nucleus (AGN) levels, there is an anticorrelation between Gamma and L/LEdd, opposite to the trend which is exhibited by high-z AGN (quasars). The turning point in the Gamma - L/LEdd LLAGN + quasars relation occurs near Gamma ~ 1.5 and L/LEdd ~ 0.01. Interestingly, this is identical to what stellar mass X-ray binaries exhibit, indicating that the authors have probably found the first empirical evidence for an intrinsic switch in the accretion mode, from advection-dominated flows to standard (disk/corona) accretion modes in supermassive black hole accretors, similar to what has been seen and proposed to happen in stellar mass black hole systems. The anticorrelation the authors find between Gamma and L/LEdd may instead indicate that stronger accretion correlates with greater absorption. Therefore, the trend for softer spectra toward more luminous, high-redshift, and strongly accreting (L/LEdd >~ 0.01) AGNs/quasars could simply be the result of strong selection biases reflected in the dearth of type 2 quasar detections. The cross-match of all ChaMP sky regions imaged by Chandra/ACIS with the SDSS DR4 spectroscopic footprint results in a parent sample of 15,955 galaxies on or near a chip and a subset of 199 sources that are X-ray detected. Among those, only 107 sources have an off-axis angle (OAA) Theta <0.2 degrees and avoid ccd=8 due to high serial readout noise; these 107 objects comprise the main sample that the authors employ for this study and that are listed in this table. The authors performed direct spectral fits to the X-ray counts distribution using the full instrument calibration, known redshift, and Galactic 21-cm column nHGal. Source spectra were extracted from circular regions with radii corresponding to energy encircled fractions of ~90%, while the background region encompasses a 20 arcsec annulus, centered on the source, with separation 4 arcsecs, from the source region. Any nearby sources were excised, from both the source and the background regions. The spectral fitting was done via yaxx ('Yet Another X-ray eXtractor': Aldcroft 2006, BAAS, 38, 376), an automated script that employs the CIAO Sherpa tool. Each spectrum was fitted in the range 0.5 - 8 keV by two different models: (1) a single power law plus absorption fixed at the Galactic 21-cm value (model 'PL'), and (2) a fixed power law of photon index Gamma = 1.9 plus intrinsic absorption of column nH (model 'PLfix'). For the nine objects with more than 200 counts, the authors employed a third model in which both the slope of the power law and the intrinsic absorption were free to vary (model 'PL_abs'). This table was created by the HEASARC in January 2012 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJ/705/1336/">CDS Catalog J/ApJ/705/1336/</a> file table1.dat. This is a service provided by NASA HEASARC .

2. GALEX/SDSS z=0.5-1.5 QSO Candidates Catalog

ID:: ivo://nasa.heasarc/glxsdssqs2
Title:: GALEX/SDSS z=0.5-1.5 QSO Candidates Catalog
Short Name:: GLXSDSSQS2
Date:: 07 Mar 2025
Publisher:: NASA/GSFC HEASARC
Description:: A sample of ~60,000 objects from the combined Sloan Digital Sky Survey-Galaxy Evolution Explorer (SDSS-GALEX) database with UV-optical colors that should isolate QSOs in the redshift range 0.5 to 1.5 is discussed. The authors use SDSS spectra of a subsample of ~ 4,500 to remove stellar and galaxy contaminants in the sample to a very high level, based on the 7-band photometry. In their paper, they discuss the distributions of redshift, luminosity, and reddening of the 19,100 QSOs (~96%) that they estimate to be present in their final sample of 19,812 point sources. This latter catalog is available in the present table. This paper is based on archival data from the Galaxy Evolution Explorer (GALEX) which is operated for NASA by the California Institute of Technology under NASA contract NAS5-98034, and on data from the SDSS. This table was created by the HEASARC in March 2011 based on the electronic version of Table 2 from the reference paper which was obtained from the AJ web site. Some of the values for the name parameter in the HEASARC's implementation of this table were corrected in April 2018. This is a service provided by NASA HEASARC .

3. Optically-Selected QSOS NVSS-Detected Source Catalog

ID:: ivo://nasa.heasarc/osqsonvss
Title:: Optically-Selected QSOS NVSS-Detected Source Catalog
Short Name:: OSQSONVSS
Date:: 07 Mar 2025
Publisher:: NASA/GSFC HEASARC
Description:: The authors used the 1.4-GHz NRAO VLA Sky Survey (NVSS) to study radio sources in two color-selected QSO samples: a volume-limited sample of 1,313 QSOs defined by Mi < -23 in the redshift range 0.2 < z < 0.45 and a magnitude-limited sample of 2,471 QSOs with mr <= 18.5 and 1.8 < z < 2.5. About 10% were detected above the 2.4-mJy NVSS catalog limit and are powered primarily by active galactic nuclei (AGNs). The space density, rho, of the low-redshift QSOs evolves as rho ~ (1 + z)6. In both redshift ranges, the flux-density distributions and luminosity functions of QSOs stronger than 2.4 mJy are power laws, with no features to suggest more than one kind of radio source. Extrapolating the power laws to lower luminosities predicts the remaining QSOs should be extremely radio quiet, but they are not. Most were detected statistically on the NVSS images with median peak flux densities Sp of ~ 0.3 mJy/beam and ~ 0.05 mJy/beam in the low- and high-redshift samples, corresponding to spectral luminosities log L1.4GHz ~ 22.7 and ~ 24.1 W/Hz, respectively. The authors suggest that the faint radio sources are powered by star formation at rates dM/dt of ~ 20 M_{sun}_/yr in the moderate luminosity (median Mi of ~ -23.4) low-redshift QSOs and dM/dt ~ 500Msun/yr in the very luminous (median Mi ~ -27.5) high-redshift QSOs. Such luminous starbursts (<log(LIR/Lsun)> ~ 11.2 and ~ 12.6, respectively) are consistent with "quasar mode" accretion in which cold gas flows fuel both AGN and starburst. The SDSS DR7 QSO catalog (Schneider et al. 2010, AJ, 139, 2360) is complete to i = 19.1 mag over a solid angle of 2.66 sr around the North Galactic Pole. It contains the small sample of 179 color-selected QSOs defined by Mi < -23 in the narrow redshift range 0.2 < z < 0.3 studied by Kimball et al. (2011, ApJ, 739, L29) and the larger sample of 1,313 QSOs in the wider redshift range 0.2 < z < 0.45 discussed here. Note that these magnitudes were calculated for an H0= 71 km/s/Mpc and OmegaM = 0.27 modern flat LambdaCDM cosmology. The entire SDSS DR7 area is covered by the NVSS, whose source catalog is complete for statistical purposes above a peak flux density Sp ~ 2.4 mJy/beam at 1.4 GHz. In the redshift range 0.2 < z < 0.45 the 45" FWHM (full width between half-maximum points) beam of the NVSS spans 150 - 250 kpc. There are 163 (12%) NVSS detections of the 1,313 QSOs in the redshift range 0.2 < z < 0.45 which are listed in Table 1 of the reference paper. The authors also chose a magnitude-limited sample of all 2,471 color-selected DR7 QSOs brighter than mr = 18.5 in the redshift range 1.8 < z < 2.5. The NVSS detected radio emission stronger than S = 2.4 mJy from only 191 (8%) of them: these are listed in Table 3 of the reference paper. This HEASARC table contains the contents of both samples described above. It thus has 163 + 191 = 354 entries, the sum of Tables 1 and 3 from the reference paper. To select only the entries from Table 1, the user should select entries with redshifts from 0.2 to 0.45. To select only the entries from Table 3, the user should select entries with redshifts > 1.8. This table was created by the HEASARC in January 2015 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJ/768/37">CDS Catalog J/ApJ/768/37</a> files table1.dat and table3.dat. This is a service provided by NASA HEASARC .

4. SDSS NBCKDE Catalog of Photometrically Selected Quasar Candidates

ID:: ivo://nasa.heasarc/sdssnbckde
Title:: SDSS NBCKDE Catalog of Photometrically Selected Quasar Candidates
Short Name:: SDSSNBCKDE
Date:: 07 Mar 2025
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 deg2 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 .

5. Sloan Digital Sky Survey Broad Absorption Line Quasars Catalog: 3rd Data Release

ID:: ivo://nasa.heasarc/sdssbalqso
Title:: Sloan Digital Sky Survey Broad Absorption Line Quasars Catalog: 3rd Data Release
Short Name:: SDSSBALQSO
Date:: 07 Mar 2025
Publisher:: NASA/GSFC HEASARC
Description:: The Sloan Digital Sky Survey (SDSS) Broad Absorption Line (BAL) Quasars Catalog (based on the 3rd SDSS Data Release) contains a total of 4784 unique BAL quasars from the SDSS DR3 (<a href="https://cdsarc.cds.unistra.fr/ftp/cats/VII/243">CDS Cat. <VII/243></a>). An automated algorithm was used to match a continuum to each quasar and to identify regions of flux at least 10% below the continuum over a velocity range of at least 1000 km/s in the C IV and Mg II absorption regions. The model continuum was selected as the best-fit match from a set of template quasar spectra binned in luminosity, emission line width, and redshift z, with the power-law spectral index and amount of dust reddening as additional free parameters. The authors characterize their sample through the traditional 'balnicity' index BI and a revised absorption index AI, as well as through parameters such as the width, outflow velocity, fractional depth, and number of troughs. From a sample of 16,883 quasars at 1.7 <= z <= 4.38, they identify 4386 (26.0%) quasars with broad C IV absorption, of which 1756 (10.4%) satisfy traditional selection criteria. From a sample of 34,973 quasars at 0.5 <= z <= 2.15, they identify 457 (1.31%) quasars with broad Mg II absorption, 191 (0.55%) of which satisfy traditional selection criteria. They find that BAL quasars may have broader emission lines on average than other quasars. 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 July 2008 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJS/165/1">CDS catalog J/ApJS/165/1</a> file table4.dat. This is a service provided by NASA HEASARC .

6. Sloan Digital Sky Survey I/II Cataclysmic Variables Catalog

ID:: ivo://nasa.heasarc/sdsscvcat
Title:: Sloan Digital Sky Survey I/II Cataclysmic Variables Catalog
Short Name:: SDSSCVCAT
Date:: 07 Mar 2025
Publisher:: NASA/GSFC HEASARC
Description:: The reference paper completed the series of cataclysmic variables (CVs) identified from the Sloan Digital Sky Survey (SDSS) I and II. The coordinates, magnitudes, and SDSS spectra of 33 more CVs were presented. Among the 33 are eight systems known prior to SDSS (CT Ser, DO Leo, HK Leo, IR Com, V849 Her, V405 Peg, PG1230+226, and HS0943+1404), as well as nine objects recently found through various photometric surveys. Among the systems identified since the SDSS are two polar candidates, two intermediate polar candidates, and one candidate for containing a pulsating white dwarf. A complete summary table of the 285 CVs with spectra from SDSS I/II which were listed in the reference paper and the 7 previous papers in the series is contained herein. This table was created by the HEASARC in January 2012 based on an electronic version of Table 6 from the reference paper which was obtained from the AJ web site. This is a service provided by NASA HEASARC .

7. Sloan Digital Sky Survey Stripe 82 Chandra Source Match Catalog

ID:: ivo://nasa.heasarc/sdsss82cxo
Title:: Sloan Digital Sky Survey Stripe 82 Chandra Source Match Catalog
Short Name:: SDSSS82CXO
Date:: 07 Mar 2025
Publisher:: NASA/GSFC HEASARC
Description:: This table contains some of the data from the latest release of the Stripe 82 X-ray (82X) survey point-source catalog, which currently covers 31.3 deg2 of the Sloan Digital Sky Survey (SDSS) Stripe 82 Legacy field. In total, 6,181 unique X-ray sources are significantly detected with XMM-Newton (> 5 sigma) and Chandra (> 4.5 sigma). This 31 deg2 catalog release includes data from XMM-Newton cycle AO 13, which approximately doubled the Stripe 82X survey area. The flux limits of the Stripe 82X survey are 8.7 x 10-16 erg s-1 cm-2, 4.7 x 10-15 erg s-1 cm-2, and 2.1 x 10-15 erg s-1 cm^=2^ in the soft (0.5 - 2.0 keV), hard (2 - 10 keV), and full (0.5 - 10 keV) bands, respectively, with approximate half-area survey flux limits of 5.4 x 10-15 erg s-1 cm-2, 2.9 x 10-14 erg s-1 cm-2, and 1.7 x 10-14 erg s-1 cm-2, respectively. The authors matched the X-ray source lists to available multi-wavelength catalogs, including updated matches to the previous release of the Stripe 82X survey; 88% of the sample is matched to a multi-wavelength counterpart. Due to the wide area of Stripe 82X and rich ancillary multi-wavelength data, including coadded SDSS photometry, mid-infrared WISE coverage, near-infrared coverage from UKIDSS and VISTA Hemisphere Survey (VHS), ultraviolet coverage from GALEX, radio coverage from FIRST, and far-infrared coverage from Herschel, as well as existing ~30% optical spectroscopic completeness, this study is beginning to uncover rare objects, such as obscured high-luminosity active galactic nuclei at high redshift. The Stripe 82X point source catalog is a valuable data set for constraining how this population grows and evolves, as well as for studying how they interact with the galaxies in which they live. The authors derive the XMM-Newton number counts distribution and compare it with their previously reported Chandra log N - log S relations and other X-ray surveys. Throughout this study, the authors adopt a cosmology of H0 = 70 km s-1 Mpc-1, OmegaM = 0.27, and Lambda = 0.73. The XMM-Newton and Chandra X-ray sources were matched with sources in the SDSS, WISE, UKIDSS, VHS, GALEX, FIRST and Herschel databases using the maximum likelihood estimator (MLE) method, as discussed in detail in Section 4 of the reference paper. This table contains the list of 1,146 Chandra sources detected in the SDSS Stripe 82. A related table SDSSS82XMM contains the list of 5,220 XMM-Newton sources detected in the SDSS Stripe 82. This table was initially created by the HEASARC in April 2014 based on the machine-readable version of the table ('Properties of SDSS Quasars Detected by Chandra') described in Appendix B1 of the reference paper (LaMassa et al. 2013, MNRAS, 436, 3581) which was obtained from the CDS (their catalog J/MNRAS/436/3581/ file chands82.dat). The present version was created by the HEASARC in January 2017 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJ/817/172">CDS Catalog J/ApJ/817/172</a> file chandra.dat. This is a service provided by NASA HEASARC .

8. Sloan Digital Sky Survey/UKIRT DSS Large Area Survey Matched Quasars Catalog

ID:: ivo://nasa.heasarc/sdsslasqso
Title:: Sloan Digital Sky Survey/UKIRT DSS Large Area Survey Matched Quasars Catalog
Short Name:: SDSSLASQSO
Date:: 07 Mar 2025
Publisher:: NASA/GSFC HEASARC
Description:: This table contains a catalog of over 130,000 quasar candidates with near-infrared (NIR) photometric properties, with an areal coverage of approximately 1200 deg2. This is achieved by matching the Sloan Digital Sky Survey (SDSS) in the optical ugriz bands to the UKIRT Infrared Digital Sky Survey (UKIDSS) Large Area Survey (LAS) in the NIR YJHK bands. The authors match the ~1 million SDSS DR6 Photometric Quasar catalog to Data Release 3 of the UKIDSS LAS (ULAS) and produce a catalog with 130,827 objects with detections in one or more NIR bands, of which 74,351 objects have optical and K-band detections and 42,133 objects have the full nine-band photometry. The majority (~85%) of the SDSS objects were not matched simply because these were not covered by the ULAS. The positional standard deviation of the SDSS Quasar to ULAS matches is 0.1370 arcseconds in RA and 0.1314 arcseconds in Dec. The authors find an absolute systematic astrometric offset between the SDSS Quasar catalog and the UKIDSS LAS, of |RA offset| = 0.025 arcseconds and |Dec offset| = 0.040 arcseconds; they suggest the nature of this offset to be due to the matching of catalog, rather than image, level data. Their matched catalog has a surface density of ~53 deg-2 for K <= 18.27 objects; tests using this matched catalog, along with data from the UKIDSS Deep Extragalactic Survey, imply that its limiting magnitude is i ~ 20.6. Color-redshift diagrams, for the optical and NIR, show a close agreement between this matched catalog and recent quasar color models at redshift z <~ 2.0, while at higher redshifts, the models generally appear to be bluer than the mean observed quasar colors. This table was created by the HEASARC in September 2012 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/AJ/141/105">CDS Catalog J/AJ/141/105</a> file table4.dat. This is a service provided by NASA HEASARC .

9. Sloan Digital Sky Survey Unusual Quasars Catalog

ID:: ivo://nasa.heasarc/sdssunuqsr
Title:: Sloan Digital Sky Survey Unusual Quasars Catalog
Short Name:: SDSSUNUQSR
Date:: 07 Mar 2025
Publisher:: NASA/GSFC HEASARC
Description:: Large spectroscopic surveys have discovered very peculiar and hitherto unknown types of active galactic nuclei (AGN). Such rare objects may hold clues to the accretion history of the supermassive black holes at the centres of galaxies. The authors aim to create a sizeable sample of unusual quasars from the unprecedented spectroscopic database of the Sloan Digital Sky Survey (SDSS). This table contains a catalog of 1005 quasars with unusual spectra in the redshift interval from 0.6 to 4.3. [HEASARC Note: the redshifts in this table actually range from 0.497 to 4.771]. The quasars were selected from the Sloan Digital Sky Survey Data Release 7 (Abazajian et al., 2009, ApJS, 182, 543) by means of Kohonen self-organising maps. The spectra are dominated by either broad absorption lines (42%), unusual red continua (27%), weak emission lines (18%), or conspicuously strong optical and/or UV iron emission (11%). This large sample provides a useful resource for both studying properties and relations of/between different types of unusual quasars and selecting particularly interesting objects, even though the compilation is not aimed at completeness in a quantifiable sense. The spectra are grouped into seven types. The catalogue contains the redshift, the absolute magnitude, the spectral type, the radio loudness parameter, a peculiarity index, and some comments on peculiar spectral features. This table was created by the HEASARC in May 2012 based on CDS table J/A+A/541/A77 file table3.dat. This is a service provided by NASA HEASARC .

10. VLA 6-GHz Observations of Low-Redshift SDSS QSOs

ID:: ivo://nasa.heasarc/lowzvlqvla
Title:: VLA 6-GHz Observations of Low-Redshift SDSS QSOs
Short Name:: LOWZVLQVLA
Date:: 07 Mar 2025
Publisher:: NASA/GSFC HEASARC
Description:: This table contains results from 6-GHz Jansky Very Large Array (JVLA) observations covering a volume-limited sample of 178 low-redshift (0.2 < z <0.3) optically selected quasi-stellar objects (QSOs). These 176 radio detections fall into two clear categories: (1) about 20% are radio-loud QSOs (RLQs) with spectral luminosities of L6 >~ 1023.2 W/Hz that are primarily generated in the active galactic nucleus (AGN) responsible for the excess optical luminosity that defines a bona fide QSO; and (2) the remaining 80% that are radio-quiet QSOs (RQQs) that have 1021 <~ L6 <~ 1023.2 W/Hz and radio sizes <~ 10 kpc, and the authors suggest that the bulk of their radio emission is powered by star formation in their host galaxies. "Radio-silent" QSOs (L_6_<~ 1021 W/Hz) are rare, so most RQQ host galaxies form stars faster than the Milky Way; they are not "red and dead" ellipticals. Earlier radio observations did not have the luminosity sensitivity of L6 <~ 1021 W/Hz that is needed to distinguish between such RLQs and RQQs. Strong, generally double-sided radio emission spanning >> 10 kpc was found to be associated with 13 of the 18 RLQ cores with peak flux densities of Sp > 5 mJy/beam (log(L) >~ 24). The radio luminosity function of optically selected QSOs and the extended radio emission associated with RLQs are both inconsistent with simple "unified" models that invoke relativistic beaming from randomly oriented QSOs to explain the difference between RLQs and RQQs. Some intrinsic property of the AGN or their host galaxies must also determine whether or not a QSO appears radio-loud. The authors have reprocessed the VLA observations of a sample of SDSS QSOs discussed in Kimball et al. (2011, ApJ, 739, L29). These were obtained using the VLA C configuration with a central frequency of 6 GHz and a bandwidth of 2 GHz in each of the two circular polarizations: with natural weighting the synthesized beam width was 3.5 arcseconds FWHM. The authors generated a catalog of radio sources associated with each QSO. They detected radio emission at 6 GHz from all but two of the 178 color-selected SDSS QSOs contained in this volume-limited sample of QSOs more luminous than Mi = -23 and with redshifts 0.2 < z < 0.3. All calculations in the reference paper assume a flat LambdaCDM cosmology with H0 = 70 km s-1 Mpc-1 and OmegaLambda = 0.7. Spectral luminosities are specified by their source-frame frequencies, flux densities are specified in the observer's frame, and a mean spectral index of alpha = d(log S)/d(log nu) = -0.7 is used to make frequency conversions This table was created by the HEASARC in April 2017 based upon the <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJ/831/168">CDS Catalog J/ApJ/831/168</a> file table1.dat. This is a service provided by NASA HEASARC .

Search

Search Constraints

Search Results

1. CHAMP/SDSS Nearby Low-Luminosity AGN Catalog

2. GALEX/SDSS z=0.5-1.5 QSO Candidates Catalog

3. Optically-Selected QSOS NVSS-Detected Source Catalog

4. SDSS NBCKDE Catalog of Photometrically Selected Quasar Candidates

5. Sloan Digital Sky Survey Broad Absorption Line Quasars Catalog: 3rd Data Release

6. Sloan Digital Sky Survey I/II Cataclysmic Variables Catalog

7. Sloan Digital Sky Survey Stripe 82 Chandra Source Match Catalog

8. Sloan Digital Sky Survey/UKIRT DSS Large Area Survey Matched Quasars Catalog

9. Sloan Digital Sky Survey Unusual Quasars Catalog

10. VLA 6-GHz Observations of Low-Redshift SDSS QSOs

Limit your search

Subject

Publisher

Resource Type

Content Level

Facility

Validation Level

Capability Type

Result Type