- ID:
- ivo://nasa.heasarc/ccosrssfag
- Title:
- Chandra COSMOS Radio-Selected Star-Forming Galaxies and AGN Catalog
- Short Name:
- CCOSRSSFAG
- Date:
- 28 Feb 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- X-ray surveys contain sizable numbers of star-forming galaxies, beyond the AGN which usually make up the majority of detections. Many methods to separate the two populations are used in the literature, based on X-ray and multi-wavelength properties. The authors aim at a detailed test of the classification schemes and to study the X-ray properties of the resulting samples. They build on a sample of galaxies selected at 1.4 GHz in the VLA-COSMOS survey, classified by Smolcic et al. (2008, ApJS, 177, 14) according to their optical colors and also observed by Chandra. A similarly selected control sample of AGN is also used for comparison. The authors review some X-ray based classification criteria and check how they affect the sample composition. The efficiency of the classification scheme devised by Smolcic et al. (2008) is such that ~30% of composite/misclassified objects are expected because of the higher X-ray brightness of AGN with respect to galaxies. The latter fraction is actually 50% in the X-ray detected sources, while it is expected to be much lower among X-ray undetected sources. Indeed, the analysis of the stacked spectrum of undetected sources shows, consistently, strongly different properties between the AGN and galaxy samples. X-ray based selection criteria are then used to refine both samples. The radio/X-ray luminosity correlation for star-forming (SF) galaxies is found to hold with the same X-ray/radio ratio valid for nearby galaxies. Some evolution of the ratio may be possible for sources at high redshift or high luminosity, though it is likely explained by a bias arising from the radio selection. Finally, in their paper the authors discuss the X-ray number counts of star-forming galaxies from the VLA- and C-COSMOS surveys according to different selection criteria, and compare them to the similar determination from the Chandra Deep Fields. The classification scheme proposed here may find application in future works and surveys. This table contains the catalogs of radio-selected SF- and AGN-candidate sources with an X-ray detection in C-COSMOS which were contained in Tables 2 and 3 of the reference paper, respectively. The HEASARC has merged these into a single table, adding a new parameter sample which is set to 'SFG' for radio-selected SF-candidate sources from Table 2 and to 'AGN' for the AGN-candidate sources from Table 3. This table was created by the HEASARC in June 2012 based on CDS table J/A+A/542/A16 files table2.dat and table3.dat. This is a service provided by NASA HEASARC .
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2582. Chandra COSMOS survey I.
- ID:
- ivo://CDS.VizieR/J/ApJS/184/158
- Title:
- Chandra COSMOS survey I.
- Short Name:
- J/ApJS/184/158
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Chandra COSMOS Survey (C-COSMOS) is a large, 1.8Ms, Chandra program that has imaged the central 0.5deg^2^ of the COSMOS field (centered at 10h, +02d) with an effective exposure of ~160ks, and an outer 0.4deg^2^ area with an effective exposure of ~80ks. The limiting source detection depths are 1.9x10^-16^erg/cm2/s in the soft (0.5-2keV) band, 7.3x10^-16^erg/cm2/s in the hard (2-10keV) band, and 5.7x10^-16^erg/cm2/s in the full (0.5-10keV) band. Here we describe the strategy, design, and execution of the C-COSMOS survey, and present the catalog of 1761 point sources detected at a probability of being spurious of <2x10^-5^ (1655 in the full, 1340 in the soft, and 1017 in the hard bands). By using a grid of 36 heavily (~50%) overlapping pointing positions with the ACIS-I imager, a remarkably uniform (+/-12%) exposure across the inner 0.5deg^2^ field was obtained, leading to a sharply defined lower flux limit. The widely different point-spread functions obtained in each exposure at each point in the field required a novel source detection method, because of the overlapping tiling strategy, which is described in a companion paper. This method produced reliable sources down to a 7-12 counts, as verified by the resulting logN-logS curve, with subarcsecond positions, enabling optical and infrared identifications of virtually all sources, as reported in a second companion paper.
- ID:
- ivo://nasa.heasarc/chandfn2ms
- Title:
- Chandra Deep Field North 2-Megasecond Catalog
- Short Name:
- Chan/DF2N
- Date:
- 28 Feb 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The Chandra Deep Field North (CDFN) 2-Megasecond Catalog contains the point sources found in the ~2 Megasecond (Ms) exposure of the Chandra Deep Field North, currently the deepest X-ray observation of the universe in the 0.5 -8.0 keV band. Five hundred and three (503) X-ray sources were detected over an ~448 square arcminute area in up to seven X-ray bands. Twenty (20) of these X-ray sources lie in the central ~5.3 square arcminute Hubble Deep Field North (13600 (+3800,-3000) sources/deg<sup>2</sup>). The on-axis sensitivity limits are ~2.5x10<sup>-17</sup> ergs/cm<sup>2</sup>/s (0.5 - 2.0 keV) and 1.4x10<sup>-16</sup> ergs/cm<sup>2</sup>/s (2 - 8 keV). Source positions are determined using matched-filter and centroiding techniques; the median positional uncertainty is ~0.3". The X-ray colors of the detected sources indicate a broad variety of source types, although absorbed AGN (including a small number of possible Compton-thick sources) are clearly the dominant type. The average backgrounds in the 0.5 - 2.0 keV and 2 - 8 keV bands are 0.056 and 0.135 counts Ms<sup>-1</sup> pixel<sup>-1</sup>, respectively. The background count distributions are very similar to Poisson distributions. This 2 Ms exposure is approximately photon limited in all seven X-ray bands for regions close to the aim point. This observation does not suffer from source confusion within ~6 arcminutes of the aim point. This table was created by the HEASARC in April 2004 based on CDS catalog table J/AJ/126/539/cdfn.dat. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/chandfn1ms
- Title:
- Chandra Deep Field North 1-Megasecond Catalog
- Short Name:
- ChanDF
- Date:
- 28 Feb 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table is the Chandra Deep Field North 1-Megasecond Catalog. It lists point sources detected in an extremely deep X-ray survey (1 Ms) of the Hubble Deep Field North (HDF-N) and its environs (~450 square arcminutes) which has been performed with the Advanced CCD Imaging Spectrometer on board the Chandra X-Ray Observatory. This is one of the two deepest X-ray surveys ever performed; for point sources near the aim point, it reaches 0.5 - 2.0 keV and 2 - 8 keV flux limits of ~3 x 10<sup>-17</sup> and ~2 x 10<sup>-16</sup> ergs cm-2 s-1, respectively. 370 distinct point sources have been detected: 360 in the full (0.5 - 8.0 keV) band, 325 in the soft (0.5 - 2.0 keV) band, 265 in the hard (2 - 8 keV) band, and 145 in the ultrahard (4 - 8 keV) band. Source positions are accurate to within 0.6 - 1.7 arcseconds (at ~90% confidence), depending mainly on the off-axis angle. Source densities of 7100 (+1100, -940) deg<sup>-2</sup> (at 4.2 x 10<sup>-17</sup> ergs cm<sup>-2</sup> s<sup>-1</sup>) and 4200 (+670, -580) deg<sup>-2</sup> (at 3.8 x 10<sup>-16</sup> ergs cm<sup>-2</sup> s<sup>-1</sup>) are observed in the soft and hard bands, respectively. This online catalog was created by the HEASARC in March 2002 based on a machine-readable version of Table 3 of Brandt et al. (2001) that was obtained from the Astronomical Journal website. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/cdfn2msnew
- Title:
- Chandra Deep Field North 2-Megasecond Improved Point Source Catalog
- Short Name:
- CDFN2MSNEW
- Date:
- 28 Feb 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains the improved point-source catalog for the 2-Ms Chandra Deep Field-North (CDF-N) Survey, implementing a number of recent improvements in Chandra source-cataloguing methodology. For the CDF-N, the main catalog (entries from which are indicated with parameter values of source_sample = "Main" in this HEASARC representation) contains 683 X-ray sources detected with wavdetect at a false-positive probability threshold of 10<sup>-5</sup> that also satisfy a binomial-probability source-selection criterion of P <= 0.004. Such an approach maximizes the number of reliable sources detected: a total of 196 main-catalog sources are new compared to the Alexander et al. (2003, AJ, 126, 539) CDF-N main catalog. The authors also provide a CDF-N supplementary catalog that consist of 72 sources (entries from which are indicated with parameter values of source_sample = "Supp" in this HEASARC representation) detected at the same wavdetect threshold and having P of 0.004-0.1 and K<sub>s</sub> <= 22.9 mag counterparts. For all 755 CDF-N sources, including the 234 newly detected ones (these being generally fainter and more obscured), the authors determine X-ray source positions utilizing centroid and matched-filter techniques; they also provide multi-wavelength identifications, apparent magnitudes of counterparts, spectroscopic and/or photometric redshifts, basic source classifications, and estimates of observed active galactic nucleus and galaxy source densities around respective field centers. Simulations show that the CDF-N main catalog is highly reliable and reasonably complete. Background and sensitivity analyses indicate that the on-axis mean flux limits reached represent a factor of ~1.5-2.0 improvement over the previous CDF-N limit. The 2 Ms CDF-N consists of a total of 20 separate Chandra observations taken between 1999 November 13 and 2002 February 22 with ACIS (see Alexander et al., 2003, AJ, 126, 539 for more details). This table was created by the HEASARC in August 2016 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJS/224/15">CDS Catalog J/ApJS/224/15</a> files table3.dat (the main source catalog) and table6.dat (the supplementary source catalog). This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/cdfn2msoid
- Title:
- ChandraDeepFieldNorth2-MegasecondOptical&IRCatalog
- Short Name:
- Chan/DF2S
- Date:
- 28 Feb 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The Chandra Deep Field North (CDFN) 2-Megasecond (2Ms) Optical and IR Catalog is an optical and near-infrared catalog for the X-ray sources in the 2Ms Chandra observation of the Hubble Deep Field North region. It has high-quality multicolor imaging data for all 503 X-ray point sources in the X-ray-selected catalog and reliable spectroscopic redshifts for 284. The authors have spectroscopically identified six high-redshift (z > 1) type II quasars (L<sub>2-8keV</sub> > 10<sup>44</sup> ergs/s) in their sample. The spectroscopic completeness for the R <= 24 sources is 87%. The spectroscopic redshift distribution shows two broad redshift spikes that have clearly grown over those originally seen in the 1Ms exposure. The spectroscopically identified extragalactic sources already comprise 75% of the measured 2-8 keV light. Redshift slices versus 2-8 keV flux show that an impressive 54% of the measured 2-8 keV light arises from sources at z < 1 and 68% from sources at z < 2. The X-ray sample is presented in Alexander et al. (2003, AJ, 126, 539, hereafter ABB2003) and in <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/AJ/126/539">CDS Catalog <J/AJ/126/539></a>, and is also available in the HEASARC Browse system as the CHANDFN2MS table. The optical imaging data consist of Johnson B, Johnson V, Cousins R, Cousins I, and Sloan z' observations obtained with the Subaru prime-focus camera Suprime-Cam on the Subaru 8.2m telescope during February-April of 2001 and 2002. This table was created by the HEASARC in April 2004 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/AJ/126/632/table1a">CDS Catalog J/AJ/126/632/table1a</a>.dat. This is a service provided by NASA HEASARC .
- ID:
- ivo://CDS.VizieR/J/AJ/122/2810
- Title:
- Chandra Deep Field North Survey. V.
- Short Name:
- J/AJ/122/2810
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- An extremely deep X-ray survey (~1Ms) of the Hubble Deep Field North (HDF-N) and its environs (~450arcmin^2^) has been performed with the Advanced CCD Imaging Spectrometer (ACIS) on board the Chandra X-Ray Observatory. This is one of the two deepest X-ray surveys ever performed; for point sources near the aim point, it reaches 0.5-2.0 and 2-8keV flux limits of ~3x10^-17^ and ~2x10^-16^ergs/cm^2^/s, respectively. Here we provide source catalogs, along with details of the observations, data reduction, and technical analysis. Observing conditions, such as background, were excellent for almost all of the exposure. We have detected 370 distinct point sources: 360 in the 0.5-8.0keV band, 325 in the 0.5-2.0keV band, 265 in the 2-8keV band, and 145 in the 4-8keV band. Two new Chandra sources in the HDF-N itself are reported and discussed. Source positions are accurate to within 0.6"-1.7" (at ~90% confidence), depending mainly on the off-axis angle. We also detect two highly significant extended X-ray sources and several other likely extended X-ray sources. We present basic number count results for sources located near the center of the field. Source densities of 7100^+1100^_-940_deg^-2^ (at 4.2x10^-17^ergs/cm^2^/s) and 4200^+670^_580_deg^-2^ (at 3.8x10^-16^ergs/cm^2^/s) are observed in the soft and hard bands, respectively.
- ID:
- ivo://CDS.VizieR/J/AJ/124/2351
- Title:
- Chandra Deep Field North survey. XII
- Short Name:
- J/AJ/124/2351
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate the relationship between faint X-ray and 1.4GHz radio source populations detected within 3' of the Hubble Deep Field (North) using the 1Ms Chandra (Cat. <J/AJ/122/2810>) and 40{mu}Jy VLA (Cat. <J/ApJ/533/611>) surveys. Within this region, we find that ~42% of the 62 X-ray sources have radio counterparts and ~71% of the 28 radio sources have X-ray counterparts; thus, a 40{mu}Jy VLA survey at 1.4GHz appears to be well matched to a 1Ms Chandra observation.
- ID:
- ivo://nasa.heasarc/cdfn2msoi2
- Title:
- ChandraDeepFieldNorthUpdatedOptical&IRCatalog
- Short Name:
- CDFN2MSOI2
- Date:
- 28 Feb 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains the redshift catalog for the X-ray sources detected in the Chandra Deep Field-North (CDF-N). The catalog for the CDF-N includes redshifts from previous work. The authors have extended the redshift information for the full sample using photometric redshifts. The goal of the OPTX Project is to use this survey, together with the Chandra Large-Area Synoptic X-Ray Survey (CLASXS) and the Chandra Lockman Area North Survey (CLANS), which are among the most spectroscopically complete surveys to date, to analyze the effect of spectral type on the shape and evolution of the X-ray luminosity functions and to compare the optical spectral types with the X-ray spectral properties. The CLANS and CLASXS surveys bridge the gap between the ultra-deep pencil-beam surveys, such as the Chandra Deep Fields, and the shallower, very large-area surveys. This table also contains updated optical and infrared photometric data for the X-ray sources in the CDF-N. Typical photometric uncertainties are given in Section 3.6 of the reference paper (Trouille et al. 2008). The X-ray information for the sources detected in the CDF-N 2-megasecond exposure which was published in Alexander et al. (2003, AJ, 126, 539) is available as the HEASARC CHANDFN2MS table, while the earlier catalog which listed information about optical and infrared counterparts (Barger et al. 2003, AJ, 126, 632) is available as the HEASARC CDFN2MSOID table. This table was created by the HEASARC in January 2009 based on the electronic version of Table 13 from the paper which was obtained from the ApJ web site. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/cdfsagncxo
- Title:
- Chandra Deep Field South AGN Spectral Properties Catalog
- Short Name:
- CDFSAGNCXO
- Date:
- 28 Feb 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains the results of a detailed X-ray spectral analysis of the sources in the 1 Ms catalog of the Chandra Deep Field South (CDFS, Giacconi et al. 2002, <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJS/139/369">CDS Cat. J/ApJS/139/369</a>, available in Browse as the CHANDFS1MS table), taking advantage of optical spectroscopy and photometric redshifts for 321 extragalactic sources out of the total sample of 347 sources. As a default spectral model, the authors adopt a power law with a slope Gamma with an intrinsic redshifted absorption N<sub>H</sub>, a fixed Galactic absorption and an unresolved Fe emission line. For 82 X-ray bright sources, they are able to perform the X-ray spectral analysis leaving both Gamma and N<sub>H</sub> free. The weighted mean value for the slope of the power law is 1.75 +/- 0.02, and the distribution of best fit values shows an intrinsic dispersion of 0.30. The authors do not find hints of a correlation between the spectral index Gamma and the intrinsic absorption column density N<sub>H</sub>. They then investigate the absorption distribution for the whole sample, deriving the N<sub>H</sub> values in faint sources by fixing Gamma to be 1.8. The authors find that the fraction of absorbed sources (with N<sub>H</sub> > 10<sup>22</sup> cm<sup>-2</sup>) in the sample is constant (at the level of about 75%) or moderately increasing with redshift. Finally, they compare the optical classification to the X-ray spectral properties, confirming that the correspondence of unabsorbed (absorbed) X-ray sources to optical type I (type II) AGN is accurate for at least 80% of the sources with spectral identification (1/3 of the total X-ray sample). This table was created by the HEASARC in August 2007 primarily based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/451/457">CDS Catalog J/A+A/451/457</a> file table1.dat. The positions of the X-ray sources were taken from <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJS/139/369">CDS Catalog J/ApJS/139/369</a> (Giacconi et al. 2002), except for that of source number 901 which was taken from Table 5 of Szokoly et al. (2004, ApJS, 155, 271). This is a service provided by NASA HEASARC .
![To the extent possible under law, the publisher has waived all copyright and related or neighboring rights to the catalogue of astrometric microlensing events. For details, see the `Creative Commons CC0 1.0 Public Domain dedication <http://creativecommons.org/publicdomain/zero/1.0/>`_. Of course, you should still give proper credit when using this data as required by good scientific practice. .. image:: /static/img/cc0.png :alt: [CC0]](/registry-search/?f%5BcapabilityType_facet%5D%5B%5D=Simple+Cone+Search&f%5Brights_facet%5D%5B%5D=To+the+extent+possible+under+law%2C+the+publisher+has+waived+all+copyright+and+related+or+neighboring+rights+to+the+catalogue+of+astrometric+++microlensing+events.++For+details%2C+see+the+%60Creative+Commons+CC0+1.0+Public+Domain+dedication+%3Chttp%3A%2F%2Fcreativecommons.org%2Fpublicdomain%2Fzero%2F1.0%2F%3E%60_.++Of+course%2C+you+should+still+give+proper+credit+when+using+this+data+as+required+by+good+scientific+practice.%0A%0A..+image%3A%3A+%2Fstatic%2Fimg%2Fcc0.png%0A+++%3Aalt%3A+%5BCC0%5D%0A%0A){kind=link}