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. =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^-15^erg/cm^2^/s). SEXSI, which studies sources selected from more than 2deg^2^, provides an essential complement to the Chandra Deep Fields, which reach depths of 5x10^-16^erg/cm^2^/s (2-10keV) but over a total area of less than 0.2deg^2^. 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{deg}) and with declinations accessible to the optical facilities available to us (DE>-20{deg}). 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: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- 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 -------------------------------------------------------------------------------- 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 -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 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) -------------------------------------------------------------------------------- Byte-by-byte Description of file: table4.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 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^-15^erg/cm^2^/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^-15^erg/cm^2^/s 122-127 F6.3 --- HRRatio Hardness ratio (1) 132 I1 --- CFlag [0/1] Cluster flag (2) -------------------------------------------------------------------------------- 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. -------------------------------------------------------------------------------- Byte-by-byte Description of file: table6.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 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^-15^erg/cm^2^/s -------------------------------------------------------------------------------- History: From electronic version of the journal References: Eckart et al., Paper II 2005ApJS..156...35E, Cat. ================================================================================ (End) Greg Schwarz [AAS], Patricia Bauer [CDS] 19-Dec-2003