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ROSAT Radio-Loud Quasars Catalog
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 .
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ROSAT All-Sky Survey/ASIAGO-ESO QSO Survey Catalog
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This table contains some of the first results of a survey for bright quasars (V < 14.5 and R < 15.4) covering the northern hemisphere at Galactic latitudes |b| > 30 degrees. The photometric database is derived from the Guide Star and USNO catalogs. Quasars are identified on the basis of their X-ray emission measured in the ROSAT All-Sky Survey (RASS). The surface density of quasars brighter than 15.5 magnitudes turns out to be (10 +/- 2) x 10-3 degrees-2, about 3 times higher than that estimated by the Palomar-Green (PG) survey. In the paper, the quasar optical luminosity function (LF) at 0.04 < z <= 0.3 is computed and shown to be consistent with a luminosity-dependent luminosity evolution of the type derived by La Franca & Cristiani (1997AJ....113.1517L) in the range 0.3 < z <=2.2. The predictions of semianalytical models of hierarchical structure formation agree remarkably well with the present observations. This table was created by the HEASARC in September 2010 based on the combination of the electronic versions of Tables 2, 3, and 4 from the reference paper which were obtained from the CDS (their catalog J/AJ/119/2540). This is a service provided by NASA HEASARC .
Sloan Digital Sky Survey Quasars Detected by Chandra
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The authors have studied the spectral energy distributions and evolution of a large sample of optically selected quasars from the Sloan Digital Sky Survey (SDSS) that were observed in 323 Chandra images analyzed by the Chandra Multiwavelength Project (ChaMP). Their highest-confidence matched sample (which this HEASARC table comprises) includes 1135 X-ray detected quasars in the redshift range 0.2 < z < 5.4, representing some 36 Msec of effective exposure. In their paper, the authors provide catalogs of QSO properties, and describe their novel method of calculating X-ray flux upper limits and effective sky coverage. Spectroscopic redshifts are available for about 1/3 of the detected sample; elsewhere, redshifts are estimated photometrically. The authors have detected 56 QSOs with redshift z > 3, substantially expanding the known sample. They find no evidence for evolution out to z ~ 5 for either the X-ray photon index Gamma or for the ratio of optical/UV to X-ray flux Alpha_ox. About 10% of detected QSOs show best-fit intrinsic absorbing columns greater than 1022 cm-2, but the fraction might reach ~1/3 if most nondetections are absorbed. The authors confirm a significant correlation between Alpha_ox and optical luminosity, but it flattens or disappears for fainter (M_B >~ -23) active galactic nucleus (AGN) alone. They report significant hardening of Gamma both toward higher X-ray luminosity, and for relatively X-ray loud quasars. These trends may represent a relative increase in nonthermal X-ray emission, and their findings thereby strengthen analogies between Galactic black hole binaries and AGN. For uniformly selected subsamples of narrow-line Seyfert 1s and narrow absorption line QSOs, they find no evidence for unusual distributions of either Alpha_ox or Gamma. Much more information on the SDSS is available at the project's web site at http://www.sdss.org/. This table was created by the HEASARC in April 2009 based on the machine-readable version of Table 2 ('Properties of SDSS Quasars Detected by Chandra') which was obtained from the ApJ website. This is a service provided by NASA HEASARC .
Optically Selected Radio-Intermediate and Loud Quasars X-ray Emission Catalog
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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 RL values (33% of objects have RL = log(Lr/Lo) = 3 - 5), where Lr and Lo 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 (RL >~ 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 <= RL < 2; consequently, the objects they classify as RLQs satisfy RL >= 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 H0 = 70 km s-1 Mpc-1, OmegaM = 0.3, and OmegaLambda = 0.7 throughout their study. This table was created by the HEASARC in October 2012 based on CDS Catalog J/ApJ/726/20 file table1.dat. This is a service provided by NASA HEASARC .
Large Quasar Astrometric Catalog, 3rd Release
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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, CDS Cat. I/313). 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 H0 = 70 km s-1 Mpc-1, OmegaM = 0.3, OmegaLambda = 0.7, and q0 = -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, CDS Cat. J/A+A/494/799) and a little more than the number of quasars recorded in the up-dated version of the Veron-Cetty and Veron (2010, CDS Cat. VII/258, 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 H0 = 72 km s-1 Mpc-1 and q0 = -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
Sloan Digital Sky Survey Broad Absorption Line Quasars Catalog: 3rd Data Release
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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 (CDS Cat. ). 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 http://www.sdss.org/. This table was created by the HEASARC in July 2008 based on CDS catalog J/ApJS/165/1 file table4.dat. This is a service provided by NASA HEASARC .
Swift Simultaneous UV, Optical, and X-Ray Observed Quasar Catalog
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The authors have compiled a catalog of optically selected quasars with simultaneous observations in UV/optical and X-ray bands by the Swift Gamma-ray Burst Explorer. Objects in this catalog are identified by matching the Swift pointings with the Sloan Digital Sky Survey (SDSS) Data Release 5 (DR5) quasar catalog. The final catalog contains 843 objects, among which 637 have both Ultraviolet Optical Telescope (UVOT) and X-Ray Telescope (XRT) observations and 354 of which are detected by both instruments. The overall X-ray detection rate is ~ 60% which rises to ~ 85% among sources with at least 10 ks of XRT exposure time. The authors construct the time-averaged spectral energy distribution (SED) for each of the 354 quasars using UVOT photometric measurements and XRT spectra. From model fits to these SEDs, they find that the big blue bump contributes about ~ 0.3 dex to the quasar luminosity. The authors re-visit the alphaox - L2500A relation by selecting a clean sample with only Type 1 radio-quiet quasars; the dispersion of this relation is reduced by at least 15% compared with studies that use non-simultaneous UV/optical and X-ray data. They find only a weak correlation between Lbol/LEdd and alphaUV. They do not find significant correlations between alphax and alphaox, alphaox and alphaUV, and alphax and log L(0.3-10 keV). The correlations between alphaUV and alphax, alphaox and alphax, alphaox and alphaUV, Lbol/LEdd and alphax, and Lbol/LEdd and alphaox are stronger among low-redshift quasars, indicating that these correlations are likely driven by the changes of SED shape with accretion state. This quasar sample was compiled in the following steps: 1. Candidate objects for the catalog were selected as any SDSS DR5 quasar that lie within 20 arcminutes of the center of the Swift FOV in any pointing from launch through 2008 June. 2. XRT data were processed to obtain X-ray count rates, spectra, and spectral parameters. 3. UVOT data were processed to obtain UV and optical photometry. 4. UVOT photometry were supplemented with measurements at other wavelengths from published catalogs. 5. Quasar SEDs were constructed. 6. Additional parameters were calculated based on the SEDs of each quasar. The raw sample is constructed by matching 3.5 years Swift pointings and the SDSS DR5 quasar catalog and contains 1034 objects. This HEASARC version of this catalog contains all 1034 objects in the "raw" catalog. To select only the 843 objects in the "final" catalog, the user should specify catalog_flag = 1 in any searches of this table. This table was created by the HEASARC in August 2012 based on an electronic version of Table 8 from the reference paper which was obtained from the ApJS web site. This is a service provided by NASA HEASARC .
All-Sky Optical Catalog of Radio/X-Ray Sources
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The Quasars.org (QORG) Catalog is an all-sky optical catalog of radio/X-ray sources. The QORG Catalog aligns and overlays the year 2001/2 releases of the ROSAT HRI, RASS, PSPC and WGA X-ray catalogs, the NVSS (2002), FIRST (2003) and SUMSS (2003) radio catalogs, the Veron QSO catalog (2003) and various galaxy/star reference catalogs onto the optical APM and USNO-A catalogs. This catalog displays calculated percentage probabilities for each optical, radio/X-ray associated object of its likelihood of being a quasar, galaxy, star, or erroneous radio/X-ray association. This table contains the main Master QORG catalog (master.dat) and contains all 501,756 radio/X-ray associated optical objects and known quasars which are optically detected in APM/USNO-A. Up to six radio/X-ray catalog identifications are presented for each optical object, plus any double radio lobes (21,498 of these). These are superimposed (and laterally fitted) onto a 670,925,779-object optical background which combines APM and USNO-A data. Other subsets of this master catalog are available at the CDS, including the Free-Lunch catalog, a concise easy-to-read variant of the Master catalog showcasing just one X-ray and/or radio identification for each object, a subset catalog of QSO candidates, and a subset catalog of known QSOs/galaxies/stars. Objects presented in this catalog are those optical APM/USNO-A objects which are associated with X-ray/radio detections, or any optically-found catalogued QSO/AGN/Bl Lac objects, which have confidence levels >40% of being radio/X-ray emitting optical objects. There are 501,756 objects included in all (including 48,285 catalogued quasars), representing the 99.4% coverage of the sky which is available from the APM and USNO-A. Each object is shown as one entry giving the position in equatorial coordinates, red and blue optical magnitudes (recalibrated) and PSF class, calculated probabilities of the object being, separately, a quasar, galaxy, star, or erroneous radio/X-ray association, any radio identification from each of the NVSS, FIRST and SUMSS surveys, including candidate double-lobe detections, any X-ray identification from each of the ROSAT HRI, RASS, PSPC and WGA surveys, including fluxes and field shifts of those identifications, plus, if already catalogued, the object name and redshift where applicable. The QORG catalog and supporting data can be accessed from the catalog home page at http://quasars.org/qorg-data.htm Questions or comments on the catalog contents may be directed to the first author Eric Flesch at eric@flesch.org. The authors request that researchers using this catalog make a small acknowledgement of such use in any published papers which thereby result. This table was created by the HEASARC in November 2004 based on CDS Catalog J/A+A/427/387 file master.dat.gz. This is a service provided by NASA HEASARC .
Sloan Digital Sky Survey NBC Quasar Candidate Catalog
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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 http://www.sdss.org/. 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 .
Atacama Cosmology Telescope 2008 Survey 148-GHz Extragalactic Source Catalog
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This table contains a list of extragalactic radio sources detected in a 455 square-degree map of the southern sky made at a frequency of 148 GHz from the Atacama Cosmology Telescope (ACT) 2008 observing season. This catalog has 157 sources with flux densities spanning two orders of magnitude from 15 to 1500 mJy. Comparison to other catalogs shows that 98% of the ACT detections correspond to sources detected at lower radio frequencies. Three of the sources appear to be associated with the brightest cluster galaxies of low redshift X-ray selected galaxy clusters. Estimates of the radio to mm-wave spectral indices and differential counts of the sources further bolster the hypothesis that they are nearly all radio sources, and that their emission is not dominated by re-emission from warm dust. In a bright (>50 mJy) 148 GHz-selected sample with complete cross-identifications from the Australia Telescope 20-GHz survey, the authors of the study observe an average steepening of the spectra between 5, 20, and 148 GHz with median spectral indices of alpha5-20 = -0.07 +/- 0.06, alpha20-148 = -0.39 +/- 0.04, and alpha5-148 = -0.20 +/- 0.03. When the measured spectral indices are taken into account, the 148-GHz differential source counts are consistent with previous measurements at 30 GHz in the context of a source count model dominated by flat spectrum radio sources. Extrapolating with an appropriately rescaled model for the radio source counts, the Poisson contribution to the spatial power spectrum from synchrotron-dominated sources with flux density less than 20 mJy is CSync = (2.8 +/- 0.3) x 10-6 microKelvin2. This table was created by the HEASARC in January 2011 based on an electronic version of Table A1 from the paper (the Point Source Catalog) which was obtained from the LAMBDA website at http://lambda.gsfc.nasa.gov/product/suborbit/act_prod_table.cfm This is a service provided by NASA HEASARC .
Sloan Digital Sky Survey/UKIRT DSS Large Area Survey Matched Quasars Catalog
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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 CDS Catalog J/AJ/141/105 file table4.dat. This is a service provided by NASA HEASARC .