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VeronCatalogofQuasars&AGN,13thEdition
This database table contains the 13th edition of the Catalog of Quasars and Active Galactic Nuclei by Veron-Cetty and Veron, and is an update of the previous versions. As in the previous editions, no information about absorption lines or X-ray properties is given, but absolute magnitides are provided, assuming a Hubble constant H<sub>0</sub> = 71 km/s/Mpc and a deceleration parameter q<sub>0</sub> = 0 (notice the change of cosmology from previous editions in which H<sub>0</sub> was assumed to be 50 km/s/Mpc). The present edition of this catalog contains 133336 quasars, 1374 BL Lac objects and 34231 active galaxies (including 15627 Seyfert 1 galaxies), for a grand total of 168941 objects, significantly more than the number of objects listed in the 12th edition (108080). The 13th edition includes positions and redshifts, as well as photometry (U, B, and V) and 6-cm and 20-cm flux densities, when available. 178 objects once proposed but now rejected as quasars are NOT included in the online version of this catalog: their names and positions are listed in the file <a href="https://cdsarc.cds.unistra.fr/ftp/cats/VII/258/reject.dat">https://cdsarc.cds.unistra.fr/ftp/cats/VII/258/reject.dat</a>. This HEASARC table also does NOT contain the additional information on gravitationally lensed quasars and quasar pairs listed in Tables 3 and 4 of the published paper: these tables are available in electronic form at the CDS <a href="https://cdsarc.cds.unistra.fr/ftp/cats/VII/248/">https://cdsarc.cds.unistra.fr/ftp/cats/VII/248/</a> files table2.dat and table3.dat (sic). The present edition of this catalog contains quasars with measured redshift known prior to July 1st, 2009. This online catalog was created by the HEASARC in April 2010 based on machine-readable tables obtained from the CDS (their catalog VII/258, files qso.dat, bllac.dat, and agn.dat). It was last updated in June 2012 to tweak some class values. This is a service provided by NASA HEASARC .
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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
M 17 Chandra X-Ray Point Source Catalog
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This table contains some of the results from a Chandra ACIS observation of the stellar populations in and around the M17 H II region. The field reveals 886 sources (listed in the present table) with observed X-ray luminosities (uncorrected for absorption) between ~ 29.3 erg s-1 < log LX < 32.8 erg s-1, 771 of which have stellar counterparts in infrared images. Spectral analysis results for the 598 brightest X-ray sources which have photometric significance of 2.0 or greater) are also given herein. For 546 of the X-ray sources, the fits used the "wabs(apec)" thermal plasma model in XSPEC assuming scaled 0.3 times solar photospheric abundances, while for the other 52 X-ray sources for which either the thermal model poorly described the data or required nonphysical parameters and the X-ray source was not identified with a known stellar counterpart, the fits used the "wabs(powerlaw)" model in XSPEC. In addition to the comprehensive tabulation of X-ray source properties, several other results were presented in the reference paper: 1. The X-ray luminosity function is calibrated to that of the Orion Nebula Cluster population to infer a total population of roughly 8000-10,000 stars in M17, one-third lying in the central NGC 6618 cluster. 2. About 40% of the ACIS sources are heavily obscured with AV > 10 mag. Some are concentrated around well-studied star-forming regions -- IRS 5/UC1, the Kleinmann-Wright Object, and M17-North -- but most are distributed across the field. As previously shown, star formation appears to be widely distributed in the molecular clouds. X-ray emission is detected from 64 of the hundreds of Class I protostar candidates that can be identified by near- and mid-infrared colors. These constitute the most likely protostar candidates known in M17. 3. The spatial distribution of X-ray stars is complex: in addition to the central NGC 6618 cluster and well-known embedded groups, we find a new embedded cluster (designated M17-X), a 2 pc long arc of young stars along the southwest edge of the M17 H II region, and 0.1 pc substructure within various populations. These structures may indicate that the populations are dynamically young. 4. All (14/14) of the known O stars but only about half (19/34) of the known B0-B3 stars in the M17 field are detected. These stars exhibit the long-reported correlation between X-ray and bolometric luminosities of LX ~ 10-7 Lbol. While many O and early-B stars show the soft X-ray emission expected from microshocks in their winds or moderately hard emission that could be caused by magnetically channeled wind shocks, six of these stars exhibit very hard thermal plasma components (kT > 4 keV) that may be due to colliding wind binaries. More than 100 candidate new OB stars are found, including 28 X-ray detected intermediate- and high-mass protostar candidates with infrared excesses. 5. Only a small fraction (perhaps 10%) of X-ray selected high- and intermediate-mass stars exhibit K-band-emitting protoplanetary disks, providing further evidence that inner disks evolve very rapidly around more massive stars. This table was created by the HEASARC in December 2007 based on electronic versions of Tables 1, 2, 3, 4 and 5 of the reference paper which were obtained from the electronic ApJ web site. This is a service provided by NASA HEASARC .
Morphological Galaxy Catalog
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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 .
M 51 Chandra X-Ray Discrete Source Catalog
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NGC 1068 Chandra X-Ray Compact Source Catalog
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This table contains some of the results from a study of the compact X-ray source population in the Seyfert 2 galaxy NGC 1068, imaged with a 50-ks Chandra observation. The authors find a total of 84 compact sources on the ACIS-S3 chip, of which 66 are located within the 25.0 B-mag/arcsec2 isophote of the galactic disk of NGC 1068. In the reference paper, the spectra of the 21 X-ray sources with at least 50 counts were modeled with both multicolor disk blackbody and power-law models. The power-law model provides the better description of the spectrum for 18 of these sources. For fainter sources, the spectral index was estimated from the hardness ratio. Five sources have 0.4-8 keV intrinsic luminosities greater than 1039 ergs s-1, assuming that their emission is isotropic and that they are associated with NGC 1068. The authors refer to these sources as intermediate-luminosity X-ray objects (IXOs). If these five sources are X-ray binaries accreting with luminosities that are both sub-Eddington and isotropic, then the implied source masses are >~7 solar masses, and so they are inferred to be black holes. Most of the spectrally modeled sources have spectral shapes similar to Galactic black hole candidates. However, the brightest compact source in NGC 1068 has a spectrum that is much harder than that found in Galactic black hole candidates and other IXOs. The brightest source also shows large amplitude variability on both short-term and long-term timescales, with the count rate possibly decreasing by a factor of 2 in ~2 ks during this Chandra observation, and the source flux decreasing by a factor of 5 between this observation and the grating observations taken just over 9 months later. The ratio of the number of sources with luminosities greater than 2.1 x 1038 ergs s-1 in the 0.4-8 keV band to the rate of massive (>5 solar masses) star formation is the same, to within a factor of 2, for NGC 1068, the Antennae, NGC 5194 (the main galaxy in M51), and the Circinus galaxy. This suggests that the rate of production of X-ray binaries per massive star is approximately the same for galaxies with currently active star formation, including "starbursts." The authors were concerned with the study of the discrete X-ray source population in NGC 1068, imaged within the 8.4 arcmin x 8.4 arcmin (35.3 kpc x 35.3 kpc) field of view of the ACIS S3 chip. Images were extracted from the reprocessed level 2 events file in soft (0.4-1.5 keV), hard (1.5-5.0 keV) and full (0.4-5.0 keV) energy bands. The authors used the CIAO program wavdetect to search the images in the three energy bands for discrete sources of X-ray emission. They analyzed the images using wavelet scales in the range from 1 pixel (0.492 arcsec) to 16 pixels (7.87 arcsec), separated by a factor of sqrt(2). The wavelet source detection threshold was set to 10-6, which gives approximately one false source for the whole S3 chip. The total number of sources detected by wavdetect in the soft, hard, and full energy band images was 115, 67, and 138, respectively. Each of these sources was examined carefully by eye, and only those 84 sources that appear compact to the eye are included in this source list. This table was created by the HEASARC in August 2015 based on the CDS Catalog J/ApJ/591/138 file table1.dat. This is a service provided by NASA HEASARC .