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CLANS - Chandra Lockman Area North Survey (CLANS) X-Ray Source Catalog

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Overview

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 Browse table). The nine ACIS-I fields which constitute the CLANS cover a solid angle of ~0.6 deg2 and reach fluxes of 7 x 10-16 ergs cm-2 s-1 (0.5-2 keV) and 3.5 x 10-15 ergs cm-2 s-1 (2-8 keV). The authors find a total of 761 X-ray point sources. The CLANS and CLASXS surveys bridge the gap between the ultradeep 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 deg2 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.


Catalog Bibcode

2008ApJS..179....1T

References

The OPTX Project. I. The Flux and Redshift Catalogs for the CLANS, CLASXS, and
CDF-N Fields.
   Trouille L., Barger A.J., Cowie L.L., Yang Y., Mushotzky R.F.
  <Astrophys. J. Suppl., 179, 1-18 (2008)>
  =2008ApJS..179....1T

Provenance

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.

Parameters

Source_Number
The CLANS source identification number, a unique identifier in ascending order of J2000 Right Ascension.

Name
The CLANS source designation, based on the 'CLANS' prefix and the source number, as recommended by the CDS Dictionary of Nomenclature of Celestial Objects.

RA
The Right Ascension of the X-ray source in the selected equinox. This was given in J2000.0 coordinates to a precision of 10-5 degrees (0.036 arcsec) in the reference paper.

Dec
The Declination of the X-ray source in the selected equinox. This was given in J2000.0 coordinates to a precision of 10-5 degrees (0.036 arcsec) in the reference paper.

LII
The Galactic Longitude of the X-ray source.

BII
The Galactic Latitude of the X-ray source.

RA_Error
The 95% confidence error in the Right Ascension from wavdetect, in arcseconds.

Dec_Error
The 95% confidence error in the Declination from wavdetect, in arcseconds.

SB_Flux_Limit
This flag parameter is set to '<' if the corresponding flux parameter is an upper limit rather than a measured value.

SB_Flux
The source X-ray flux in the 0.5-2.0 keV band, in units of erg cm-2 s-1. The errors quoted are the 1-sigma Poisson errors, using the approximations from Gehrels (1986, ApJ, 303, 336). They do not include the uncertainty in the flux conversion factor; however, the errors are generally dominated by the Poisson errors.

SB_Flux_Neg_Err
The 1-sigma Poisson lower error in the corresponding flux of the X-ray source, in units of erg cm-2 s-1.

SB_Flux_Pos_Err
The 1-sigma Poisson upper error in the corresponding flux of the X-ray source, in units of erg cm-2 s-1

HB_Flux_Limit
This flag parameter is set to '<' if the corresponding flux parameter is an upper limit rather than a measured value.

HB_Flux
The source X-ray flux in the 2.0-8.0 keV band, in units of erg cm-2 s-1. The errors quoted are the 1-sigma Poisson errors, using the approximations from Gehrels (1986, ApJ, 303, 336). They do not include the uncertainty in the flux conversion factor; however, the errors are generally dominated by the Poisson errors.

HB_Flux_Neg_Err
The 1-sigma Poisson lower error in the corresponding flux of the X-ray source, in units of erg cm-2 s-1

HB_Flux_Pos_Err
The 1-sigma Poisson upper error in the corresponding flux of the X-ray source, in units of erg cm-2 s-1

FB_Flux
The source X-ray flux in the 0.5-8.0 keV band, in units of erg cm-2 s-1. The errors quoted are the 1-sigma Poisson errors, using the approximations from Gehrels (1986, ApJ, 303, 336). They do not include the uncertainty in the flux conversion factor; however, the errors are generally dominated by the Poisson errors.

FB_Flux_Neg_Err
The 1-sigma Poisson lower error in the corresponding flux of the X-ray source, in units of erg cm-2 s-1

FB_Flux_Pos_Err
The 1-sigma Poisson upper error in the corresponding flux of the X-ray source, in units of erg cm-2 s-1

Hardness_Ratio_Limit
This flag parameter is set to '<' or '>' if the hardness ratio is an upper or lower limit, respectively, rather than a measured value.

Hardness_Ratio
The X-ray source hardness ratio HR, defined as HR = CR(2-8 keV)/CR(0.5-2 keV), where CR(2-8 keV) and CR(0.5-2 keV) are the count rates in the specified energy bands.

Hardness_Ratio_Neg_Err
The 1-sigma Poisson lower error in the hardness radio of the X-ray source, as propagated from the 1-sigma errors in the counts in the hard and soft bands.

Hardness_Ratio_Pos_Err
The 1-sigma Poisson upper error in the hardness radio of the X-ray source, as propagated from the 1-sigma errors in the counts in the hard and soft band.

Spectral_Index
The power-law photon index Gamma of the X-ray source as derived from the value of the hardness ratio.

Spectral_Index_Neg_Err
The 1-sigma Poisson lower error in the power-law photon index of the X-ray source, as propagated from the 1-sigma errors in the counts in the hard and soft bands.

Spectral_Index_Pos_Err
The 1-sigma Poisson upper error in the power-law photon index of the X-ray source, as propagated from the 1-sigma errors in the counts in the hard and soft bands.

SB_Counts
The net counts of the X-ray source in the 0.5-2 keV energy band. The errors quoted are the 1-sigma Poisson errors, using the approximations from Gehrels (1986, ApJ, 303, 336)

SB_Counts_Neg_Err
The 1-sigma Poisson lower error in the 0.5-2 keV band counts of the X-ray source.

SB_Counts_Pos_Err
The 1-sigma Poisson upper error in the 0.5-2 keV band counts of the X-ray source.

HB_Counts
The net counts of the X-ray source in the 2-8 keV energy band. The errors quoted are the 1-sigma Poisson errors, using the approximations from Gehrels (1986, ApJ, 303, 336)

HB_Counts_Neg_Err
The 1-sigma Poisson lower error in the 2-8 keV band counts of the X-ray source.

HB_Counts_Pos_Err
The 1-sigma Poisson upper error in the 2-8 keV band counts of the X-ray source.

FB_Counts
The net counts of the X-ray source in the 0.5-8 keV energy band. The errors quoted are the 1-sigma Poisson errors, using the approximations from Gehrels (1986, ApJ, 303, 336).

FB_Counts_Neg_Err
The 1-sigma Poisson lower error in the 0.5-8 keV band counts of the X-ray source.

FB_Counts_Pos_Err
The 1-sigma Poisson upper error in the 0.5-8 keV band counts of the X-ray source.

SB_Exposure
The effective exposure time, in seconds, at the position of the X-ray source, from the exposure map in the 0.5-2 keV band.

HB_Exposure
The effective exposure time, in seconds, at the position of the X-ray source, from the exposure map in the 2-8 keV band.

FB_Exposure
The effective exposure time, in seconds, at the position of the X-ray source, from the exposure map in the 0.5-8 keV band.

Off_Axis
The angular offset of the X-ray source from the pointing center of the observation in which the source was detected, in arcminutes.


Contact Person

Questions regarding the CLANS database table can be addressed to the HEASARC User Hotline.

Page Author: Browse Software Development Team
Last Modified: 24-May-2012