J/ApJ/596/944 SEXSI catalog (Harrison+, 2003)
The Serendipitous Extragalactic X-ray Source Identification program.
I. Characteristics of the hard X-ray sample.
Harrison F.A., Eckart M.E., Mao P.H., Helfand D.J., Stern D.
<Astrophys. J., 596, 944-956 (2003)>
=2003ApJ...596..944H 2003ApJ...596..944H
ADC_Keywords: Surveys ; X-ray sources
Mission_Name: Chandra
Keywords: catalogs - surveys - X-rays: galaxies - X-rays: general
Abstract:
The Serendipitous Extragalactic X-Ray Source Identification (SEXSI)
program is designed to extend greatly the sample of identified
extragalactic hard X-ray (2-10keV) sources at intermediate fluxes
(∼10-13 to 10-15erg/cm2/s). SEXSI, which studies sources
selected from more than 2deg2, provides an essential complement to
the Chandra Deep Fields, which reach depths of 5x10-16erg/cm2/s
(2-10keV) but over a total area of less than 0.2deg2. In this paper
we describe the characteristics of the survey and our X-ray data
analysis methodology. We present the cumulative flux distribution for
the X-ray sample of 1034 hard sources and discuss the distribution of
spectral hardness ratios. Our logN-logS in this intermediate flux
range connects to those found in the Deep Fields, and by combining the
data sets, we constrain the hard X-ray population over the flux range
in which the differential number counts change slope and from which
the bulk of the 2-10keV X-ray background arises. We further
investigate the logN-logS distribution separately for soft and hard
sources in our sample, finding that while a clear change in slope is
seen for the softer sample, the hardest sources are well described by
a single power law down to the faintest fluxes, consistent with the
notion that they lie at lower average redshift.
Description:
We selected fields with high Galactic latitude (|b|>20°) and with
declinations accessible to the optical facilities available to us
(DE>-20°). We used observations taken with the Advanced Camera for
Imaging Spectroscopy (ACIS I- and S-modes; Bautz et al., 1998, Proc.
SPIE, 3444, 210) only (for sensitivity in the hard band). All the
fields presented in this paper have data that are currently in the
Chandra public archive.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 84 27 Chandra observations
table4.dat 132 1034 Source catalog
table6.dat 84 877 Soft-band only source catalog
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See also:
B/chandra : The Chandra Archive Log (CXC, 2002)
J/AJ/122/2810 : Chandra Deep Field North Survey. 1Ms catalog (Brandt+, 2001)
J/AJ/126/539 : Chandra Deep Fields North & South. 2Ms Cat. (Alexander+, 2003)
J/ApJS/139/369 : Chandra Deep Field South. 1Ms catalog (Giacconi+, 2002)
J/ApJS/156/35 : SEXSI catalog. II (Eckart+, 2005)
J/ApJS/165/19 : SEXSI catalog. III (Eckart+, 2006)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 12 A12 --- Galaxy Target galaxy name
14- 34 A21 --- MType Morphological type
36- 41 F6.4 --- z ? Redshift
43- 46 I4 km/s cz ? Heliocentric velocity
48- 49 I2 h RAh Right ascension (J2000.0)
51- 52 I2 min RAm Right ascension (J2000.0)
54- 55 I2 s RAs Right ascension (J2000.0)
57 A1 --- DE- Declination sign (J2000.0)
58- 59 I2 deg DEd Declination (J2000.0)
61- 62 I2 arcmin DEm Declination (J2000.0)
64- 65 I2 arcsec DEs Declination (J2000.0)
67- 70 F4.1 10+20cm-2 NH Galactic hydrogen column density
72- 74 I3 ks ExpTime Exposure time (Total: 1648ks)
76- 90 A15 --- Chips ACIS chips (Total: 134)
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 16 A16 --- CXOSEXSI The IAU-registered name (JHHMMSS.s+DDMMSS)
20- 21 I2 h RAh Hour of Right Ascension (J2000)
23- 24 I2 min RAm Minute of Right Ascension (J2000)
26- 30 F5.2 s RAs Second of Right Ascension (J2000)
33 A1 --- DE- Sign of the Declination (J2000)
34- 35 I2 deg DEd Degree of Declination (J2000)
37- 38 I2 arcmin DEm Arcminute of Declination (J2000)
40- 43 F4.1 arcsec DEs Arcsecond of Declination (J2000)
46- 50 F5.2 arcmin OAA Off axis angle
53- 59 F7.2 ct Hcts Background subtracted hard band (2.1-7keV)
counts
62- 67 F6.2 ct HBk Estimated background counts within hard
counts extraction aperture
71- 75 F5.2 --- HSNR Signal-to-noise ratio of the hard detection
78- 84 F7.2 aW/m2 HFlux Unabsorbed hard band (2.0-10keV) flux
in units of 10-15erg/cm2/s
86- 93 F8.2 ct Scts Background subtracted soft
band (0.3-2.1keV) counts
96-101 F6.2 ct SBk Estimated background counts within soft
counts extraction aperture
104-109 F6.2 --- S/N Signal-to-noise ratio of the soft detection
111-118 F8.2 aW/m2 SFlux Unabsorbed soft band (0.5-2.0keV) flux
in units of 10-15erg/cm2/s
122-127 F6.3 --- HRRatio Hardness ratio (1)
132 I1 --- CFlag [0/1] Cluster flag (2)
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Note (1): Ratio = (H-S)/(H+S) where
H is the corrected counts in the 2.0-10keV band, and
S is the corrected counts in the 0.5-2.0keV band.
Note (2): Cluster flag:
1 = source falls within 1Mpc of a cluster center;
0 = source doesn't fall within 1Mpc of a cluster center.
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Byte-by-byte Description of file: table6.dat
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Bytes Format Units Label Explanations
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1- 16 A16 --- CXOSEXSI IAU-registered name (JHHMMSS.s+DDMMSS)
20- 21 I2 h RAh Hour of Right Ascension (J2000)
23- 24 I2 min RAm Minute of Right Ascension (J2000)
26- 30 F5.2 s RAs Second of Right Ascension (J2000)
33 A1 --- DE- Sign of the Declination (J2000)
34- 35 I2 deg DEd Degree of Declination (J2000)
37- 38 I2 arcmin DEm Arcminute of Declination (J2000)
40- 43 F4.1 arcsec DEs Arcsecond of Declination (J2000)
46- 50 F5.2 arcmin OAA Off axis angle
53- 59 F7.2 ct Scts Background subtracted soft band (0.5-2.1keV)
counts
61- 67 F7.2 ct SBk Estimated background counts within soft counts
extraction aperture
70- 75 F6.2 --- SSNR Signal-to-noise ratio of the soft detection
78- 84 F7.2 aW/m2 SFlux Unabsorbed soft (0.5-2.0keV) flux,
in units of 10-15erg/cm2/s
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History:
From electronic version of the journal
References:
Eckart et al., Paper II 2005ApJS..156...35E 2005ApJS..156...35E, Cat. J/ApJS/156/35
(End) Greg Schwarz [AAS], Patricia Bauer [CDS] 19-Dec-2003