IX/45 The Chandra Source Catalog, Release 1.1 (Evans+ 2012)
The Chandra Source Catalog, Release 1.1
Evans I.N., Primini F.A., Glotfelty C.S., Anderson C.S., Bonaventura N.R.,
Chen J.C., Davis J.E., Doe S.M., Evans J.D., Fabbiano G., Galle E.C.,
Gibbs D.G., Grier J.D., Hain R.M., Hall D.M., Harbo P.N., He X.,
Houck J.C., Karovska M., Kashyap V.L., Lauer J., McCollough M.L.,
McDowell J.C., Miller J.B., Mitschang A.W., Morgan D.L., Mossman A.E.,
Nichols J.S., Nowak M.A., Plummer D.A., Refsdal B.L., Rots A.H.,
Siemiginowska A., Sundheim B.A., Tibbetts M.S., Van Stone D.W.,
Winkelman S.L., Zografou P.
<Astrophys. J. Suppl. Ser. 189, 37 (2010)>
=2010ApJS..189...37E 2010ApJS..189...37E
=2014yCat.9045....0E 2014yCat.9045....0E
ADC_Keywords: X-ray sources ; Surveys ;
Mission_Name: Chandra
Keywords: catalogs; X-rays: general
Abstract:
The Chandra Source Catalog (CSC) is a general purpose virtual X-ray
astrophysics facility that provides access to a carefully selected set
of generally useful quantities for individual X-ray sources, and is
designed to satisfy the needs of a broad-based group of scientists,
including those who may be less familiar with astronomical data
analysis in the X-ray regime. The first release of the CSC includes
information about 94,676 distinct X-ray sources detected in a subset
of public Advanced CCD Imaging Spectrometer imaging observations from
roughly the first eight years of the Chandra mission. This release of
the catalog includes point and compact sources with observed spatial
extents ≲30''. The catalog (1) provides access to the best estimates
of the X-ray source properties for detected sources, with good
scientific fidelity, and directly supports scientific analysis using
the individual source data; (2) facilitates analysis of a wide range
of statistical properties for classes of X-ray sources; and (3)
provides efficient access to calibrated observational data and
ancillary data products for individual X-ray sources, so that users
can perform detailed further analysis using existing tools. The
catalog includes real X-ray sources detected with flux estimates that
are at least 3 times their estimated 1-σ uncertainties in at
least one energy band, while maintaining the number of spurious
sources at a level of ≲1 false source per field for a 100ks
observation. For each detected source, the CSC provides commonly
tabulated quantities, including source position, extent, multi-band
fluxes, hardness ratios, and variability statistics, derived from the
observations in which the source is detected. In addition to these
traditional catalog elements, for each X-ray source the CSC includes
an extensive set of file-based data products that can be manipulated
interactively, including source images, event lists, light curves, and
spectra from each observation in which a source is detected.
Description:
This version of the catalog is release 1.1. It includes the
information contained in release 1.0.1, plus point and compact source
data extracted from HRC imaging observations, and catch-up ACIS
observations released publicly prior to the end of 2009.
Request for Acknowledgment of Use of the Chandra Source Catalog:
Users are kindly requested to acknowledge in the acknowledgment
section of any resulting publications their use of the Chandra Source
Catalog. The following language is suggested:
"This research has made use of data obtained from the Chandra Source
Catalog, provided by the Chandra X-ray Center (CXC) as part of the
Chandra Data Archive"
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
csc11.dat 216 106586 The Chandra Source Catalog, Version 1.1
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See also:
http://cxc.cfa.harvard.edu/csc/ : The Chandra Source Catalog Home Page
B/chandra : The Chandra Archive Log (CXC, 1999-2013)
Byte-by-byte Description of file: csc11.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- --- [CXO]
5- 20 A16 --- CXO Chandra source name (JHHMMSS.s+DDMMSS)
22- 30 F9.5 deg RAdeg Right ascension (ICRS) of Chandra source (ra)
32- 40 F9.5 deg DEdeg Declination (ICRS) of Chandra source (dec)
43- 48 F6.2 arcsec ePos [0.03/158] Position error radius at 95%
confidence level (errellipser0)
51- 56 F6.2 --- S/N [3/] Source flux significance (highest)
(significance)
58- 68 E11.6 mW/m2 Fb ? Aperture-corrected ACIS net energy flux
(fluxaperb) (1)
70- 80 E11.6 mW/m2 b_Fb ? Lower limit of Fb (fluxaperlolim_b) (4)
82- 92 E11.6 mW/m2 B_Fb ? Upper limit of Fb (fluxaperhilim_b) (4)
94-104 E11.6 mW/m2 Fw ? Aperture-corrected HRC net energy flux
(fluxaperw) (1)
106-116 E11.6 mW/m2 b_Fw ? Lower limit of Fw (fluxaperlolim_w)
118-128 E11.6 mW/m2 B_Fw ? Upper limit of Fw (fluxaperhilim_w)
132-138 F7.4 --- hr2 [-1/1]? "hard" hardness ratio (Fh-Fm)/Fb
(hard_hm) (1)
142-148 F7.4 --- b_hr2 [-1/1]? Lower limit of hr2 (hardhmlolim)
152-158 F7.4 --- B_hr2 [-1/1]? Upper limit of hr2 (hardhmhilim)
162-168 F7.4 --- hr1 [-1/1]? "soft" hardness ratio (Fm-Fs)/Fb
(hard_ms) (1)
172-178 F7.4 --- b_hr1 [-1/1]? Lower limit of hr1 (hardmslolim)
182-188 F7.4 --- B_hr1 [-1/1]? Upper limit of hr1 (hardmshilim)
194 I1 --- fc [0/1] Confusion flag (conf_flag) (2)
200 I1 --- fe [0/1] Extension flag (extent_flag) (2)
206 I1 --- fs [0/1] Saturation flag (satsrcflag) (2)
208-209 I2 --- Vab [0/10]? ACIS intra-observation variability
(varintraindex_b) (3)
211 I1 --- Vib [0/8]? ACIS inter-observation variability
(varinterindex_b) (3)
213-214 I2 --- Vaw [0/10]? HRC intra-observation variability
(varintraindex_w) (3)
216 I1 --- Viw [0/8]? HRC inter-observation variability
(varinterindex_w) (3)
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Note (1): the bands are designated as:
--------------------------------
u = 0.2-0.5keV (ACIS ultra-soft)
s = 0.5-1.2keV (ACIS soft)
m = 1.2-2.0keV (ACIS medium)
h = 2.0-7.0keV (ACIS hard)
b = 0.5-7.0keV (ACIS broad-band)
w = 0.1-10.keV (HRC wide)
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Note (2): the flags mean 0=false, 1=true:
fc = 1 when source regions overlap
fe = 1 when deconvolved source extent is inconsistent with a
point source at the 90% confidence leve
fs = 1 when in the source is saturated in all observations;
source properties are unreliable
Note (3): Gregory-Loredo (1992ApJ...398...14G 1992ApJ...398...14G) variability indexes are
computed within an observation ("intra-observation" variability)
and between observations ("inter-observation" variability). The
variability index in the range [0,10] (values 1, 2, 9 and 10 are
not used for inter-observation variability), and the highest value
across all observations was retained for the intra-observation
variability. See section 3.12 for details. Values are:
0 = Definitely not variable
1 = Not considered variable
2 = Probably not variable
3 = May be variable
4 = Likely to be variable
5 = Considered variable
6-10 = Definitely variable
Note (4): it may happen that the flux, determined from a maximum likelihood
estimator, is outside the 1σ confidence interval of the flux
probability density function; more details can be found from
http://cxc.harvard.edu/csc/why/ap_vals_errs.html
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Acknowledgements:
Dr Ian N. Evans, CfA
(End) Francois Ochsenbein [CDS] 09-Jan-2014