ACDS V10.0 - Detailed Description of CXC/V2

ACDS V10.0 - Sun Jan 19 07:51:36 CET 2025

| # Detailed Description of CXC/V2 : Chandra Catalog Release View |

Note : this is the description file of the original catalog. This HTML page corresponds well to the original description, but some minor changes in the format may have been introduced in the FITS output files in order to allow for arithmetic operations on quantities such as coordinates and times. h:m:s and d:m:s units are normally converted into degrees, and YYYY-MM-DD into julian days.
Similarly, some slight changes may have been introduced in the units; the value given in the HTML files supersedes the value indicated in the ReadMe file for this catalogue.

    O/3         Extract from CSC 2.0 current database view
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    Extract from Chandra Source Catalog Release 2.0 (CSC 2.0) Current Database
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    ADC_Keywords: X-ray sources, Cross identifications

    Mission_Name: CHANDRA

    Description:

    The Chandra Source Catalog (CSC) is ultimately intended to be the definitive catalog of X-ray sources
    detected by the Chandra X-ray Observatory. To achieve that goal, the catalog will be released to the
    user community in a series of increments with increasing capability. The second major release of the
    CSC (release 2.0) includes data for roughly 315,000 X-ray sources on the sky extracted from 10,382
    Chandra ACIS and HRC-I imaging observations released publicly through the end of 2014.

    Users are kindly requested to acknowledge their use of the Chandra Source Catalog in any resulting
    publications. http://cxc.harvard.edu/csc2/cite.html

    The version operating at Strasbourg Observatory/CDS uses the results of an ADQL query
    http://cxc.harvard.edu/csc2/cli/index.html and only lists a subset of all columns available in the
    database view.

    File Summary:

           FileName      Lrecl  Records   Explanations

    ×                   80        .   This file
    × ReadMe           156        .   This file
    × Catalog          156        .   Result

    Byte-by-byte Description of file:  Catalog

       Bytes Format Units   Label     Explanations

       1- 20  A20   ---     Name      source name in the form "2CXO Jhhmmss.s{+|-}ddmmss"
      21- 28  D8.7  deg     ra        source position, ICRS right ascension
      29- 36  D8.7  deg     dec       source position, ICRS declination
      37- 44  D8.7  arcsec errellipser0  major radius of the 95% confidence level position error ellipse
      45- 52  D8.7  arcsec errellipser1  minor radius of the 95% confidence level position error ellipse
      53- 60  D8.7  arcsec errellipseang  position angle (referenced from local true north) of the major axis
      61- 68  F8.7  --- significance  highest flux significance across all stacked observations and science energy bands
          69  I1    ---    conf_flag  source confused ?
          70  I1    ---     ext_flag  source extended ?
          71  I1    --- satsrcflag  source saturated in all observations ?
      72- 79  E8.2 erg/s*cm2 fluxaperavg_b  aperture-corrected net fluxaveraged over all observations
      80- 87  E8.2 erg/s*cm2 fluxaperavglolimb  68% lower confidence limit of fluxaperavg
      88- 95  E8.2 erg/s*cm2 fluxaperavghilimb  68% upper confidence limit of fluxaperavg
      96-103  D8.7  ---     hard_hm   (2.0-7.0 keV) to (1.2-2.0 keV) hardness ratio
     104-111  D8.7  --- hardhmlolim  68% lower confidence limit of hard_hm
     112-119  D8.7  --- hardhmhilim  68% upper confidence limit of hard_hm
     120-127  D8.7  ---     hard_ms   (1.2-2.0 keV) to (0.5-1.2 keV) hardness ratio
     128-135  D8.7  --- hardmslolim  68% lower confidence limit of hard_ms
     136-143  D8.7  --- hardmshilim  68% upper confidence limit of hard_ms
     144-147  I4    ---     acis_num  total number of ACIS imaging observations contributing
     148-156  F9.1  ---    acis_time  total exposure time (seconds of good time)

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    (End)