- ID:
- ivo://nasa.heasarc/clasxs
- Title:
- Chandra Large-Area Synoptic X-Ray Survey of Lockman Hole-NW
- Short Name:
- Chan/Syn/LHN
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains the X-ray catalog and basic results from the wide-area, moderately deep Chandra Large Area Synoptic X-ray Survey (CLASXS) of the Lockman Hole-Northwest (LHNW) field (Yang et al. 2004), as well as the results from optical and near-infrared photometric and spectroscopic observations of these X-ray sources (Steffen et al. 2004). The nine ACIS-I fields cover a contiguous solid angle of 0.4 square degrees and reach fluxes of 5 x 10<sup>-16</sup> ergs/cm<sup>2</sup>/s (0.4 - 2 keV) and 3 x 10<sup>-15</sup> ergs/cm<sup>2</sup>/s (2 - 8 keV). (Note that fields LHNW 1-3 were observed during 2001 April 30-May 17, and that the rest of the fields were observed during 2002 April 29-May 4). This survey bridges the gap between ultra-deep pencil-beam surveys, such as the Chandra Deep Fields (CDFs), and shallower, large-area surveys, allowing a better probe of the X-ray sources that contribute most of the 2 - 10 keV cosmic X-ray background (CXB). A total of 525 X-ray point sources and four extended sources were found. There are B, V, R, I, and z' photometry for 521 (99%) of the 525 sources in the X-ray catalog and spectroscopic redshifts for 271 (52%), including 20 stars. The authors did not find evidence for redshift groupings of the X-ray sources, like those found in the Chandra Deep Field surveys, because of the larger solid angle covered by this survey. They separated the X-ray sources by optical spectral type and examined the colors, apparent and absolute magnitudes, and redshift distributions for the broad-line and non-broad-line active galactic nuclei. Combining their wide-area survey with other Chandra and XMM-Newton hard X-ray surveys, they find a definite lack of luminous, high accretion rate sources at z < 1, consistent with previous observations that showed that super-massive black hole growth is dominated at low redshifts by sources with low accretion rates. This table was created by the HEASARC in May 2005 from the merger of 3 CDS tables, corresponding to Tables 2 and 3 from Yang et al. 2005 and Table 1 of Steffen et al. (2005): <p> <pre> J/AJ/128/1501/table2.dat J/AJ/128/1501/table3.dat J/AJ/128/1483/table1.dat </pre> This is a service provided by NASA HEASARC .
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- ID:
- ivo://nasa.heasarc/clasxsoid
- Title:
- ChandraLarge-AreaSynopticX-RaySurveyOptical&IRCatalog
- Short Name:
- CLASXSOID
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains the redshift catalog for the X-ray sources detected in the Chandra Large Area Synoptic X-ray Survey (CLASXS). The catalog for the CLASXS field 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 Deep Field-North (CDF-N) 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. As a result, they probe the X-ray sources that contribute the bulk of the 2-8 keV X-ray background and cover the flux range of the observed break in the log N - log S distribution. This table also contains updated optical and infrared photometric catalogs for the X-ray sources in the CLASXS field. Note that for any source with both CFHT and Subaru data in the R and z' bands, the authors used the CFHT magnitude. Typical photometric uncertainties are given in Section 3.6 of the reference paper (Trouille et al. 2008). The X-ray information for the CLASXS catalog which was published in Yang et al. (2004, AJ, 128, 1501) is available as the HEASARC CLASXS table. This table was created by the HEASARC in January 2009 based on the electronic version of Table 12 from the paper which was obtained from the ApJ web site. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/clscat
- Title:
- Chandra Legacy Survey (CLS) Catalog
- Short Name:
- CLSCAT
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The COSMOS-Legacy survey is a 4.6-Ms Chandra program that has imaged 2.2 deg<sup>2</sup> of the COSMOS field with an effective exposure of ~160 ks over the central 1.5 deg<sup>2</sup> and of ~80 ks in the remaining area. The survey is the combination of 56 new observations obtained as an X-ray Visionary Project with the previous C-COSMOS survey. In the reference paper, the authors describe the reduction and analysis of the new observations and the properties of 2273 point sources detected above a spurious probability of 2 x 10<sup>-5</sup>. The authors also present the updated properties of the C-COSMOS sources detected in the new data. The whole survey includes 4,016 point sources (3,814, 2,920 and 2,440 in the full, soft, and hard band). The limiting depths are 2.2 x 10<sup>-16</sup>, 1.5 x 10<sup>-15</sup>, and 8.9 x 10<sup>-16</sup> erg/cm<sup>2</sup>/s in the 0.5-2, 2-10, and 0.5-10 keV bands, respectively. The observed fraction of obscured active galactic nuclei with a column density > 10<sup>22</sup> cm<sup>-2</sup> from the hardness ratio (HR) is ~ 50<sup>+17</sup>_-16_%. Given the large sample, the authors compute source number counts in the hard and soft bands, significantly reducing the uncertainties of 5% - 10%. For the first time, they compute number counts for obscured (HR > -0.2) and unobscured (HR < -0.2) sources and find significant differences between the two populations in the soft band. Due to the unprecedented large exposure, the COSMOS-Legacy area is three times larger than surveys at similar depths and its depth is three times fainter than surveys covering similar areas. The area-flux region occupied by COSMOS-Legacy is likely to remain unsurpassed for years to come. The half-a-field shift tiling strategy was designed to uniformly cover the COSMOS Hubble area in depth and point-spread function (PSF) size by combining the old C-COSMOS (Elvis et al., 2009, ApJS, 184, 158) observations with the new Chandra ones (see Figure 1 in the reference paper). The main properties of the new ACIS-I Chandra COSMOS-Legacy observations are summarized in Table 1 therein. The observations took place in four blocks: 2012 November to 2013 January; 2013 March to July; 2013 October to 2014 January; and 2014 March. The mean net effective exposure time per field was 48.8 ks after all the cleaning and reduction operations. This table was created by the HEASARC in July 2016 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJ/819/62">CDS Catalog J/ApJ/819/62</a>, file table5.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/clansoid
- Title:
- ChandraLockmanAreaNorthSurvey(CLANS)Optical&IRCatalog
- Short Name:
- CLANSOID
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains the redshift catalog for the X-ray sources detected in the Chandra Lockman Area North Survey (CLANS). The redshifts for the CLANS field are all new. For fluxes above 10<sup>-14</sup> ergs cm<sup>-2</sup> s<sup>-1</sup> (2-8 keV) the authors have redshifts for 76% of the sources in the CLANS, CLASXS, and CDF-N surveys. They extend the redshift information for the full sample using photometric redshifts. The goal of the OPTX Project is to use these three surveys, 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 optical and infrared photometric catalog for the CLANS X-ray sources is presented here (see the CLANS Browse table for the X-ray information). The CLANS and CLASXS surveys bridge the gap between the ultra-deep pencil-beam surveys, such as the CDFs, and the shallower, very large-area surveys. As a result, they probe the X-ray sources that contribute the bulk of the 2-8 keV X-ray background and cover the flux range of the observed break in the log N - log S distribution. This table was created by the HEASARC in December 2008 based on the electronic version of Table 11 from the paper which was obtained from the ApJ web site. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/clans
- Title:
- Chandra Lockman Area North Survey (CLANS) X-Ray Source Catalog
- Short Name:
- CLANS
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains the catalogs for the X-ray sources detected in the Chandra Lockman Area North Survey (CLANS). (The information on the optical and infrared counterparts to these sources is contained in the CLANSOID table.) The nine ACIS-I fields which constitute the CLANS cover a solid angle of ~0.6 deg<sup>2</sup> and reach fluxes of 7 x 10<sup>-16</sup> ergs cm<sup>-2</sup> s<sup>-1</sup> (0.5-2 keV) and 3.5 x 10<sup>-15</sup> ergs cm<sup>-2</sup> s<sup>-1</sup> (2-8 keV). The authors find a total of 761 X-ray point sources. The CLANS and CLASXS surveys bridge the gap between the ultra-deep pencil-beam surveys, such as the CDFs, and the shallower, very large-area surveys. As a result, they probe the X-ray sources that contribute the bulk of the 2-8 keV X-ray background and cover the flux range of the observed break in the log N-log S distribution. CLANS consists of nine separate 70 ks Chandra ACIS-I exposures centered at J2000.0 RA and Dec of (10 46,+59 01) (see Table 2 of the reference paper for the full observational details) which were combined to create an 0.6 deg<sup>2</sup> image containing 761 sources. The CLANS observations consist of a raster with an ~2 arcminute overlap between contiguous pointings. Following the prescription in Yang et al. (2004, AJ, 128, 1501) for the CLASXS field, the authors merged the nine individual pointing catalogs to create the final CLANS X-ray catalog. For sources with more than one detection in the nine fields, they used the detection from the observation in which the effective area of the source was the largest. This table was created by the HEASARC in December 2008 based on the electronic versions of Tables 4 and 5 from the paper which were obtained from the ApJ web site. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/champlane
- Title:
- Chandra Multiwavelength Plane Survey Optical ID Catalog
- Short Name:
- CHAMPLANE
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The authors have carried out optical and X-ray spectral analyses on a sample of 136 candidate optical counterparts of X-ray sources found in five Galactic bulge fields included in their Chandra Multiwavelength Plane (ChaMPlane) Survey. They used a combination of optical spectral fitting and quantile X-ray analysis to obtain the hydrogen column density toward each object, and a three-dimensional dust model of the Galaxy to estimate the most probable distance in each case. They present the discovery of a population of stellar coronal emission sources, likely consisting of pre-main-sequence, young main-sequence, and main-sequence stars, as well as a component of active binaries of RS CVn or BY Dra type. They identify one candidate quiescent low-mass X-ray binary with a sub-giant companion, but note that this object may also be an RS CVn system. They report the discovery of 3 new X-ray-detected cataclysmic variables (CVs) in the direction of the Galactic center (at distances <~2 kpc). This number is in excess of predictions made with a simple CV model based on a local CV space density of <~10<sup>-5</sup> pc<sup>-3</sup>, and a scale height of ~200 pc. They discuss several possible reasons for this observed excess in their paper. This table was created by the HEASARC in October 2008 based on the version of Table 5 from the paper which was obtained from the electronic ApJ web site. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/champpsc
- Title:
- Chandra Multiwavelength Project (ChaMP) Point Source Catalog
- Short Name:
- ChaMPPS
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table represents the `Main Chandra Multiwavelength Project (ChaMP) X-Ray Point Source Catalog' and contains the basic parameters, photometry, and fluxes of 6512 ChaMP sources in 130 Chandra observations from Chandra Cycles 1 and 2. This table lists fluxes for 2 assumed spectral energy distributions with the photon indices of Gamma=1.4 and Gamma=1.7. This catalog was distributed by the ChaMP team based on the "Chandra Multiwavelength Project: X-ray Point Source Catalog (Kim et al., 2007, ApJS, 169, 401)", and was downloaded from <a href="http://hea-www.harvard.edu/CHAMP/">http://hea-www.harvard.edu/CHAMP/</a>. If you have any comments/questions on this catalog, please contact mkim @ cfa.harvard.edu or dkim @ cfa.harvard.edu. The full Chandra Multiwavelength Project (ChaMP) X-ray point source catalog lists ~ 6800 X-ray sources detected in 149 Chandra observations covering ~ 10 square degrees. The full ChaMP catalog sample is 7 times larger than the initial published ChaMP catalog (Kim et al. 2004, ApJS, 150, 19). The exposure times of the fields in this sample range from 0.9 to 124 ks, corresponding to a deepest X-ray flux limit in the 0.5 - 8.0 keV band of 9 x 10<sup>-16</sup> ergs cm<sup>-2</sup> s<sup>-1</sup>. The ChaMP X-ray data were uniformly reduced and analyzed with ChaMP-specific pipelines and then carefully validated by visual inspection. The ChaMP catalog includes X-ray photometric data in eight different energy bands as well as X-ray spectral hardness ratios and colors, source reliability, detection probability, and positional uncertainties. The false source detection rate is ~1% of all detected ChaMP sources, while the detection probability is better than ~ 95% for sources with counts >~ 30 and off-axis angle <5'. The typical positional offset between ChaMP X-ray source and their SDSS optical counterparts is 0.7" +/- 0.4", derived from ~ 900 matched sources. This HEASARC table contains the main ChaMP catalog of 6512 X-ray point sources in 130 ChaMP fields observed once and in the overlapping fields which had the longest exposures. It does not contain the supplementary ChaMP catalog of 853 sources in 19 ChaMP overlapping fields with shorter exposure times. This table was created by the HEASARC in October 2006 based on the table <a href="http://hea-www.cfa.harvard.edu/CHAMP/IMAGES_DATA/champ_xpc.tab">http://hea-www.cfa.harvard.edu/CHAMP/IMAGES_DATA/champ_xpc.tab</a> on the ChaMP website. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/chpngptsrc
- Title:
- Chandra Nearby Galaxies Point Source Catalog
- Short Name:
- ChanNGalPSC
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The authors have analyzed Chandra ACIS observations of 32 nearby spiral and elliptical galaxies. The properties (e.g., counts in 3 energy bands, hardness ratios and inferred X-ray luminosities) of the 1441 X-ray point sources that were detected in these galaxies are listed in this table. The total point-source X-ray (0.3 - 8.0 keV) luminosity L<sub>XP</sub> is found to be well correlated with the B-band, K-band, and FIR+UV luminosities of spiral host galaxies, and is well correlated with the B-band and K-band luminosities of elliptical galaxies. This suggests an intimate connection between L<sub>XP</sub> and both the old and the young stellar populations, for which K and FIR+UV luminosities are reasonable proxies for the galaxy mass and the star formation rate (SFR). This table was created by the HEASARC in October 2006 based on CDS table J/ApJ/602/231/tablea1.dat This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/channsgpsc
- Title:
- Chandra Nearby Spiral Galaxies Point Source Catalog
- Short Name:
- ChanNSPiral
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- Emission from discrete point sources dominates the X-ray luminosity in spiral galaxies. This table contains the results from a survey of 11 nearby, nearly face-on spiral galaxies observed with the Chandra X-ray Observatory in 22 observations for a total of 869 ks. The galaxies in this sample are at high Galactic latitude to minimize the absorbing column in the line of site, are nearby to minimize source confusion, and span the Hubble sequence for spirals (types 0-7), allowing insights into the X-ray source population of many diverse systems. More than 820 unique point sources are detected in at least one observation within the D25 ellipses of the galaxies. A minimum of 27% of the sources exhibit detectable long- or short-term variability, indicating a source population dominated by accreting XRBs. 17 ultraluminous X-ray sources are detected, with typical rates per galaxy of 1 or 2. In this table, source lists for the 11 galaxies are presented, along with source counts, fluxes, luminosities, X-ray colors, and variability properties. It should be noted that the X-ray source counts presented in this table are raw, background-subtracted counts, so the count rates in sources from the same galaxy that fall on different CCDs cannot be directly compared. The colors presented have been corrected for the differences between front-illuminated and back-illuminated CCDs. This table was created by the HEASARC in November 2006 based on the electronic version of Table 4 obtained from the electronic ApJ web site. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/chanmaster
- Title:
- Chandra Observations
- Short Name:
- Chandra
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This database table contains all of the observations made by the Chandra X-Ray Observatory (CXO, formerly known as the Advanced X-ray Astrophysics Facility or AXAF) as part of the Performance Verification and Calibration (PVC) phase and also contains all of the subsequent Cycles' Guaranteed Time Observers (GTO) and General Observer (GO) targets, and any Director's Discretionary Time (DDT) targets that have been observed. It also includes scheduled and as-yet-not-scheduled targets. The HEASARC updates this database table on a twice-weekly basis by querying the database table at the Chandra X-Ray Center (CXC) website, as discussed in the Provenance section. For observations whose status is 'archived', data products can be retrieved from the HEASARC's mirror of the CXC's Chandra Data Archive (CDA). The CXC should be acknowledged as the source of Chandra data. The PVC phase was during the first few months of the CXO mission; some of the calibration observations that are for monitoring purposes will be performed in later mission cycles. All calibration data (entries with Type = CAL in this database) are placed immediately into the CXO public data archive at the Chandra X-Ray Observatory Center (CXC); please see the Web page at <a href="http://asc.harvard.edu/">http://asc.harvard.edu/</a> for more information on the CXC data archive). GTO observations during Cycle 1 or any subsequent Cycle will probably occupy 100% of months 3-4, 30% of months 5-22, and 15% of the available time for the remainder of the mission. Guaranteed Time Observers will have the same proprietary data rights as General Observers (i.e., their data will be placed in the public CXC archive 12 months after they have received the data in usable form). For detailed information on the Chandra Observatory and datasets see: <pre> <a href="http://cxc.harvard.edu/">http://cxc.harvard.edu/</a> for general Chandra information <a href="http://cxc.harvard.edu/cda/">http://cxc.harvard.edu/cda/</a> for the Chandra Data Archive <a href="http://cxc.harvard.edu/cal/">http://cxc.harvard.edu/cal/</a> for calibration information <a href="http://cxc.harvard.edu/caldb/">http://cxc.harvard.edu/caldb/</a> for the calibration database <a href="http://cxc.harvard.edu/ciao/">http://cxc.harvard.edu/ciao/</a> for data analysis <a href="http://cxc.harvard.edu/ciao/download/">http://cxc.harvard.edu/ciao/download/</a> for analysis software <a href="http://cxc.harvard.edu/ciao/threads/">http://cxc.harvard.edu/ciao/threads/</a> for analysis threads <a href="http://cda.harvard.edu/chaser/">http://cda.harvard.edu/chaser/</a> for WebChaSeR </pre> The HEASARC updates this database table on a twice-weekly basis based on information obtained from the Chandra Data Archive at the CXC website. This is a service provided by NASA HEASARC .
