- ID:
- ivo://nasa.heasarc/bhrfscid
- Title:
- Byurakan/Hamburg/ROSAT Catalog of Optical IDs
- Short Name:
- BHROSATOpt.
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains the Byurakan/Hamburg/ROSAT Catalog (BHRC) of the optical identifications of X-ray sources. The BHRC includes all 2791 X-ray sources from the ROSAT Faint Source Catalog (ROSAT-FSC, CDS Catalog <IX/29>) with galactic latitude |b| >= 30 degrees, declination >= 0 degrees, and ROSAT PSPC count rate CR > 0.04 ct/s. The optical identifications were carried out using the Hamburg Quasar Survey (HQS) digitized spectroscopic plates, the DSS1 and DSS2 (blue, red, and IR) images, the MAPS photometric data, the USNO-B1.0 (for proper motion), the NVSS and FIRST radio, and the IRAS and 2MASS infrared catalogs. From the DSS images, positional, brightness, color, extension, variability, and proper-motion information, the optical-to-X-ray positional offsets were obtained and a morphological classification was made. Available SIMBAD and NED data were also utilized. Cross-correlations were made with AGN, white dwarf, and cataclysmic variable catalogs (322, 8 and 7 associations, respectively). The authors managed to identify 97% of the sources (2696/2791 sources) that are associated with 3202 optical objects. 2248 X-ray sources have a single optical counterpart, 144 have a double or multiple optical counterpart (binaries, galaxy groups, etc.), and 304 have ambiguous identifications (some of the latter might actually be blends of two X-ray sources that were not resolved by ROSAT). The QSOs and AGN represent the largest group of X-ray counterparts (56.2%); bright stars (including late-type stars, but excluding WDs and CVs) are counterparts for 33.2% of the sources, and bright galaxies and groups of galaxies comprise 9.2%. A number of close galaxy pairs (possibly interacting/merging galaxies) are found as counterparts for X-ray sources (3.0%), as well as 1.0% WDs and 0.4% CVs. The BHRC may be used for the selection and study of samples of the various classes of X-ray emitters: the table gives all the available multiwavelength data for the identified sources. This table was created by the HEASARC in June 2006 based on CDS table J/A+A/449/425/table1.dat This is a service provided by NASA HEASARC .
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- ID:
- ivo://nasa.heasarc/cyder
- Title:
- Calan-Yale Deep Extragalactic Research Survey X-Ray Source Catalog
- Short Name:
- CYDER
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The main goal of the Calan-Yale Deep Extragalactic Research (CYDER) Survey X-ray survey is to study serendipitous X-ray sources detected by Chandra in an intermediate flux range (10<sup>-15</sup> to 10<sup>-12</sup> ergs/s) that comprises most of the X-ray background. A total of 267 X-ray sources spread over five archived fields were detected. The log N - log S distribution obtained for this sample is consistent with the results of other surveys. Deep V and I images were taken of these fields in order to calculate X-ray-to-optical flux ratios. Identifications and redshifts were obtained for 106 sources using optical spectroscopy from 8 m class telescopes to reach the optically faintest sources, to the same level as deeper X-ray fields like the Chandra Deep Fields, showing that the nature of sources detected depends mostly on the optical limit for spectroscopy. This table was created by the HEASARC in March 2007 based on the CDS table J/ApJ/621/104, file table4.dat. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/cgpsngpcat
- Title:
- Canadian Galactic Plane Survey (CGPS) 1420-MHz Compact Source Catalog
- Short Name:
- CGPSNGPCAT
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains a catalog of compact sources of radio emission at 1420 MHz in the northern Galactic plane from the Canadian Galactic Plane Survey (CGPS). The catalog contains 72,758 compact sources with an angular size less than 3 arcminutes within the Galactic longitude range 52 < l<sub>II</sub> < 192 degrees down to a 5-sigma detection level of ~1.2 mJy. Linear polarization properties are included for 12,368 sources with signals greater than 4 x sigma<sub>QU</sub> in the CGPS Stokes Q and U images at the position of the total intensity peak. In the reference paper, the authors compare the CGPS flux densities with the catalogued flux densities in the Northern VLA Sky Survey (NVSS) catalog for 10,897 isolated unresolved sources with CGPS flux density greater than 4 mJy in order to search for sources that show variable flux density on timescales of several years. They identify 146 candidate variables that exhibit high fractional variations between the two surveys. In addition, they identify 13 candidate transient sources that have CGPS flux density above 10 mJy but that are not detected in the NVSS. In the CGPS, the Synthesis Telescope at the Dominion Radio Astrophysical Observatory (the DRAO ST) provided arcminute-resolution images of the radio continuum and atomic-hydrogen line emission of the northern Galactic Plane. The CGPS DRAO radio continuum observations provided images of Stokes I, Q, and U in four 7.5-MHz sub-bands spanning 35 MHz, centered on 1420 MHz. The observations were carried out in three phases beginning in 1995 and ending in 2009. The sky coverage of each phase and the observing dates are listed in Table 1 of the reference paper. The Galactic plane was covered with a width in Galactic latitude of 9 degrees, centered at b<sub>II</sub> = 1 degree to accommodate the warp of the Galactic disk. The longitude coverage was constrained by the southern Declination limit of ~20 degrees, the range that could be effectively imaged by a linear east-west synthesis telescope array. The Phase II observations included an extension to higher latitudes (b<sub>II</sub> = 17.5 degrees) over a restricted range of longitude. In this table, we present the CGPS 1420-MHz compact source catalog covering 1,464 square degrees and spanning a range of 140 degrees of Galactic longitude between 52 and 192 degrees. This table was created by the HEASARC in June 2017 based upon a machine-readable version of Table 2 from the reference paper that was obtained from the AJ web site. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/candelscxo
- Title:
- CANDELS H-Band Selected Chandra Source Catalog
- Short Name:
- CANDELSCXO
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- Improving the capabilities of detecting faint X-ray sources is fundamental to increase the statistics on faint high-z AGN and star-forming galaxies. The authors performed a simultaneous maximum likelihood point-spread function (PSF) fit in the 0.5-2 keV and 2-7 keV energy bands of the 4 Ms Chandra Deep Field South (CDFS) data at the position of the 34,930 CANDELS H-band selected galaxies. For each detected source, they provide X-ray photometry and optical counterpart validation. The authors validated this technique by means of a ray-tracing simulation, and detected a total of 698 X-ray point-sources with a likelihood L > 4.98 (i.e.> 2.7sigma). They show that the prior knowledge of a deep sample of Optical-NIR galaxies leads to a significant increase of the detection of faint (i.e. ~ 10<sup>-17</sup> erg s<sup>-1</sup> cm<sup>-2</sup> in the 0.5-2 keV band) sources with respect to "blind" X-ray detections. By including previous catalogs, this work increases the total number of X-ray sources detected in the 4 Ms CDFS, CANDELS area to 793, which represents the largest sample of extremely faint X-ray sources assembled to date. These results suggest that a large fraction of the optical counterparts of our X-ray sources determined by likelihood ratio actually coincides with the priors used for the source detection. Most of the newly detected sources are likely star-forming galaxies or faint absorbed AGN. The authors identified a few sources with putative photometric redshift z > 4. Despite the low number statistics, this sample significantly increases the number of X-ray selected candidate high-z AGN. The 4-Ms CDFS consists of 23 observations described in Table 1 of Luo et al. (2008, ApJS, 179, 19) plus 31 other pointings described in Xue et al. (2011, ApJS, 195, 10, hereafter X11) for a total exposure of ~4 Ms. For the purpose of this paper, the authors employed only observations taken with a focal temperature of <= -120 C, since at higher temperatures the background cannot be modeled with their technique. This table was created by the HEASARC in July 2016 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJ/823/95">CDS Catalog J/ApJ/823/95</a> file catalog.dat. 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 .
- ID:
- ivo://nasa.heasarc/cgrabs
- Title:
- Candidate Gamma-Ray Blazar Survey Source Catalog
- Short Name:
- CGRABS
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The authors have constructed a uniform all-sky survey of bright blazars, selected primarily by their flat radio spectra, that is designed to provide a large catalog of likely gamma-ray active galactic nuclei (AGNs). The defined sample, the Candidate Gamma-Ray Blazar Survey (CGRaBS) source catalog, has 1625 targets with radio and X-ray properties similar to those of the EGRET blazars, spread uniformly across the |b| > 10 degrees sky. They also report progress toward optical characterization of the sample; of objects with known red magnitude R < 23, 85% have been classified and 81% have measured redshifts. One goal of this program is to focus attention on the most interesting (e.g., high-redshift, high-luminosity, etc.) sources for intensive multi-wavelength study during the observations by the Large Area Telescope (LAT) on the Gamma-Ray Large-Area Space Telescope (GLAST) satellite observatory. This table was created by the HEASARC in April 2008 based on an electronic version of Table 2 of the reference paper obtained from the electronic ApJS web site. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/carinaclas
- Title:
- Carina Nebula Chandra X-Ray Point Source Classes
- Short Name:
- CARINACLAS
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The Chandra Carina Complex Project (CCCP) provides a sensitive X-ray survey of a nearby starburst region over > 1 deg<sup>2</sup> in extent. Thousands of faint X-ray sources are found, many concentrated into rich young stellar clusters. However, significant contamination from unrelated Galactic and extragalactic sources is present in the X-ray catalog. In their paper, the authors describe the use of a naive Bayes classifier to assign membership probabilities to individual sources, based on source location, X-ray properties, and visual/infrared properties. For the particular membership decision rule adopted, 75% of CCCP sources are classified as members, 11% are classified as contaminants, and 14% remain unclassified. The resulting sample of stars likely to be Carina members is used in several other studies, which appear in the special issue of Astrophysical Journal Supplement (Volume 194, May 2011 Issue) which was devoted to the CCCP. This table was created by the HEASARC in June 2011 based on the electronic version of Table 5 from the reference paper which was obtained from the ApJS web site. In the input source table, the names were truncated by 3 characters from their complete version. The HEASARC corrected these names, and also obtained the Chandra source positions, using the electronic version of Table 2 from the companion paper (Broos et al. 2011, ApJS, 194, 2: available as the HEASARC Browse table CARINACXO), also obtained from the ApJS web site. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/cargm31cxo
- Title:
- Carina Nebula Gum 31 Chandra X-Ray Point Source Catalog
- Short Name:
- CARGM31CXO
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- Gum 31 is a prominent, but still rather poorly studied, HII region around the stellar cluster NGC 3324 at the northwestern periphery of the Carina nebula complex. The aim of the authors aim was to reveal and characterize the young stellar population in Gum 31. An X-ray survey is the only efficient way to identify young stars in this region, which has extremely high galactic field-star contamination, that can avoid the strong biases of infrared-excess-selected samples of disk-bearing young stars. The authors used the Chandra observatory to perform a deep (70 ks) X-ray observation of the Gum 31 region and detected 679 X-ray point sources. This extends and complements the X-ray survey of the central Carina nebula regions performed in the Chandra Carina Complex Project (CCCP, available in the HEASARC database system as the CARINACXO table). Using deep near-infrared images from their recent VISTA survey of the Carina nebula complex, their comprehensive Spitzer point-source catalog, and optical archive data, the authors identify counterparts for 75% of these X-ray sources. The aimpoint of the ACIS-I observation was set to be RA(J2000) = 10<sup>h</sup> 37<sup>m</sup> 36.6<sup>s</sup>, Dec(J2000) = -58<sup>o</sup> 41' 18". This position is close to the center of the H II region, and allows both the stellar cluster NGC 3324 and the cluster G286.38-0.26 to be in the inner parts of the field-of-view, where the point-spread function is still very good. The pointing roll angle (i.e., the orientation of the detector with respect to the celestial north direction) was 138.35<sup>o</sup>. The ACIS field-of-view is just wide enough to cover the full spatial extent of the optically bright Gum 31 H II region and some parts of the surrounding dust shell (see Fig. 1 of the reference paper). The ACIS-I field of view is 17' x 17', which corresponds to 11.3 p x 11.3 pc at the Gum 31 distance of 2.3 kpc). The total net exposure time of the observation was 68,909s (19.14 h). The details of the source detection procedures are described in Section 21. of the reference paper. The final X-ray catalog contains 679 individual point sources. The number of extracted counts ranges from 3 for the faintest sources, up to 920 for the strongest source, while the median value is 11 counts. This table contains the basic X-ray properties and near- and mid-infrared photometry of the X-ray sources detected in the Gum 31 field. The details of the IR matching to the X-ray sources are given in Sections 4.1, 4.2 and 4.3 of the reference paper. This table was created by the HEASARC in May 2014 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/564/A120">CDS Catalog J/A+A/564/A120</a> files table1.dat and table3.dat. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/carinaxmm
- Title:
- Carina OB1 Association XMM-Newton X-Ray Point Source Catalog
- Short Name:
- CARINAXMM
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This database table contains the Carina OB1 Association XMM-Newton X-Ray Point Source Catalog. The X-ray properties of the stellar population in the Carina OB1 Association have been examined with special emphasis on early-type stars. Their spectral characteristics provide some clues to understanding the nature of X-ray formation mechanisms in the winds of single and binary early-type stars. A timing and spectral analysis of five observations with XMM-Newton is performed using various statistical tests and thermal spectral models. 235 point sources have been detected within the field of view. Several of these sources are probably pre-main sequence stars with characteristic short-term variability. Seven sources are possible background AGNs. X-ray count rates in three energy bands and the X-ray variability status are given for 557 detections of the 235 point source. Cross-identifications of X-ray sources with optical and infrared catalogs are also presented. This table was created by the HEASARC in April 2008 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/477/593">CDS Catalog J/A+A/477/593</a> files table2.dat and table3.dat. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/uc7c151mhz
- Title:
- 7C Catalog 151-MHz Survey Final Unified Source Catalog
- Short Name:
- UC7C151MHZ
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains a final unified catalog for the 7C survey at 151 MHz with a spatial resolution of 70 x 70cosec(Dec) arcsec<sup>2</sup>. This has been constructed by amalgamating the existing catalogs derived from individual fields imaged at this resolution and eliminating redundancy in regions of mutual overlap. This was a non-trivial procedure because the flux in multiple-component sources may be fitted differently on alternative images, owing, for example, to differences in local noise and beam distortion. The final catalog as published thus produced contains 43683 sources. (Note that the HEASARC removed one duplicate source entry for '7C 083231.6+262635' since it had two entries, which were identical except that in one the beam-fitted flux density S<sub>bf</sub> was 834 mJy/beam, while, in the other entry now removed, S<sub>bf</sub> was 840 mJy/beam). Separate final catalogs have been previously published for the 7C Galactic Plane 7CG survey (available as the HEASARC table GP7C151MHZ), and the lower-resolution survey of the low-declination strip 9<sup>h</sup> < RA < 16<sup>h</sup>, 20<sup>o</sup> < Dec < 35<sup>o</sup> (available as the HEASARC table LD7C151MHZ). The individual catalogs for about 40 of the 96 regions contributing to the total have already been published, together with full details of the methodology, in MNRAS or A&AS: <pre> Reference Region Lacy et al. 1995, MNRAS, 276, 614 92 Visser et al. 1995, A&AS, 110, 419 93 Pooley et al. 1998, MNRAS, 298, 637 94-96 Riley et al. 1999, MNRAS, 306, 31 1-33 </pre> and these data are also available via the MRAO website: <a href="http://www.mrao.cam.ac.uk/surveys/7C/">http://www.mrao.cam.ac.uk/surveys/7C/</a> Individual catalogs for the remaining 58 regions by Riley et al. (regions 34-91) were released electronically via the MRAO website in November 2001. These include a re-analysis of data originally published in rather a different parametrization by McGilchrist et al. 1990, MNRAS, 246, 110. The regions re-analyzed are those numbered 41, 44, 59, 60, 62 and 63 and they supersede McGilchrist's 1990 publication. The RA x Dec coverage, the average rms noise, the flux density of the faintest source listed and the completeness limit for each of the individual regions contributing to the final catalog are given in the table <a href="http://cdsarc.u-strasbg.fr/ftp/cats/J_MNRAS/382/1639/regions.dat">http://cdsarc.u-strasbg.fr/ftp/cats/J_MNRAS/382/1639/regions.dat</a>. For further details of the surveys and data analysis procedures please refer to the published papers referenced above and other references contained therein. This table was created by the HEASARC in October 2010 based on CDS table J/MNRAS/382/1639 files 7c.dat and regions.dat. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/rt9cc15ghz
- Title:
- 9C Continued 15-GHz Ryle Telescope Survey of VSA Fields Source Catalog
- Short Name:
- RT9CC15GHZ
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The 9C (9th Cambridge) survey of radio sources with the Ryle Telescope at 15.2 GHz was set up to survey the fields of the cosmic microwave background telescope, the Very Small Array (VSA). In their first paper (Waldram et al. 2003, MNRAS, 342, 915), the authors described three regions of the survey, constituting a total area of 529 deg<sup>2</sup> to a completeness limit of ~ 25 mJy. In this follow-up, they present results from a series of deeper regions, constituting a total area of 115 deg<sup>2</sup> complete to ~ 10 mJy and of 29 deg<sup>2</sup> complete to ~ 5.5 mJy. The authors have investigated the source counts and the distributions of the 1.4 to 15.2 GHz spectral indices for these deeper samples. The whole catalog of 643 sources is contained in the present table. Down to their lower limit of 5.5 mJy, the authors detect no evidence for any change in the differential source count from the earlier fitted count above 25 mJy, n(S) = 51(S/Jy)<sup>-2.15</sup> Jy<sup>-1</sup> sr<sup>-1</sup>. They matched both their new and earlier catalogues with the NRAO VLA Sky Survey (NVSS) catalogue at 1.4 GHz and selected flux-limited samples at both 15 and 1.4 GHz. As they expected, they found that the proportions of sources with flat and rising spectra in the samples selected at 15 GHz are significantly higher than those in the samples selected at 1.4 GHz. In addition, for 15-GHz samples selected in three flux density ranges, they detect a significant shift in the median value of the 1.4 to 15.2 GHz spectral index: the higher the flux densities, the higher the proportions of sources with flat and rising spectra. In the area complete to ~ 10 mJy, the authors find five sources between 10 and 15 mJy at 15 GHz, amounting to 4.3 per cent of sources in this range, with no counterpart in the NVSS catalogue. This implies that, had they relied on the NVSS for locating their sources, they could have missed a significant proportion of them at low flux densities. These results illustrate the problems inherent in using a low-frequency catalog to characterize the source population at a much higher frequency and emphasize the value of a blind 15.2-GHz survey. This table was created in November 2010 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/MNRAS/404/1005">CDS catalog J/MNRAS/404/1005</a> file 9c_cont.dat. This is a service provided by NASA HEASARC .
