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J/ApJS/156/35         SEXSI catalog. II                          (Eckart+, 2005)

The serendipitous extragalactic X-ray source identification (SEXSI) program. II. Optical imaging. Eckart M.E., Laird E.S., Stern D., Mao P.H., Helfand D.J., Harrison F.A. <Astrophys. J. Suppl. Ser., 156, 35-45 (2005)> =2005ApJS..156...35E
ADC_Keywords: Surveys ; X-ray sources ; Photometry Keywords: catalogs - galaxies: active - surveys - X-rays: galaxies - X-rays: general Abstract: The Serendipitous Extragalactic X-ray Source Identification (SEXSI) Program is designed to expand significantly the sample of identified extragalactic hard X-ray sources at intermediate fluxes, 10-13ergs/cm2/s≲S2-10keV<10-15ergs/cm2/s. SEXSI, which includes sources derived from more than 2°2 of Chandra images, provides the largest hard X-ray-selected sample yet studied, offering an essential complement to the Chandra Deep Fields (total area 0.2°2). In this paper we describe R-band optical imaging of the SEXSI fields from the Palomar, MDM, and Keck observatories. We have identified counterparts or derived flux limits for nearly 1000 hard X-ray sources. Using the optical images, we derive accurate source positions. We investigate correlations between optical and X-ray flux, and optical flux and X-ray hardness ratio. We also study the density of optical sources surrounding X-ray counterparts, as well as the properties of optically faint, hard X-ray sources. Description: We have imaged the SEXSI fields using the Palomar 60inch (P60) and 200inch (P200) telescopes, the MDM 2.4m (MDM-2.4) and 1.3m (MDM-1.3) telescopes, and the Keck I telescope. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table3.dat 116 1034 Optical follow-up 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/ApJ/596/944 : SEXSI catalog (Harrison+, 2003) J/ApJS/165/19 : SEXSI catalog. III (Eckart+, 2006) Byte-by-byte Description of file: table3.dat
Bytes Format Units Label Explanations
1- 16 A16 --- CXOSEXSI IAU-registered name (JHHMMSS.s+DDMMSS) 18- 19 I2 h RAh Hour of Right Ascension (J2000) (1) 21- 22 I2 min RAm Minute of Right Ascension (J2000) (1) 24- 28 F5.2 s RAs Second of Right Ascension (J2000) (1) 30 A1 --- DE- Sign of the Declination (J2000) (1) 31- 32 I2 deg DEd Degree of Declination (J2000) (1) 34- 35 I2 arcmin DEm Arcminute of Declination (J2000) (1) 37- 40 F4.1 arcsec DEs Arcsecond of Declination (J2000) (1) 42- 46 F5.2 arcmin OAA Off-axis angle 48- 55 F8.2 10-18W/m2 HFlux Unabsorbed hard band (2.0-10keV) flux in units of 10-15erg/cm2/s 57- 61 F5.2 --- HS/N Signal-to-noise ratio of the hard detection 63- 67 F5.2 --- HR Hardness ratio (2) 69 I1 --- l_HR [0,1] Hardness ratio limit flag (3) 71 I1 --- Cl [0,1] Cluster flag (4) 73 I1 --- OID [0,6] Optical ID flag (5) 75- 79 F5.2 mag Rcmag ? The Cousins R Magnitude 81- 84 F4.2 mag e_Rcmag ? Error on Rcmag 86- 89 F4.1 mag Rclim ? Limiting Rcmag of Image 91 I1 --- f_Rcmag [0,1]? Flag on Rcmag (6) 93- 96 F4.1 arcsec oRA ? Optical counterpart RA offset from X-ray RA 98-101 F4.1 arcsec oDE ? Optical counterpart DE offset from X-ray DE 103-105 F3.1 arcsec dPos ? Position difference of optical counterpart and X-ray source 107-111 F5.2 [-] Fx/Fo ? Log of the HFlux/RFlux ratio 113-116 F4.2 --- Stell ? SExtractor stellarity fraction (7)
Note (1): X-ray positions are corrected for average X-ray to optical offset (to correct Chandra astrometry). Note (2): The hardness ratio is HR=(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 extracted at the position of the hard band detection. Note (3): The hardness ratio flag is defined as follows: 1 = hardness ratio is a lower limit, 0 = hardness ratio is solid (not a limit). Note (4): Cluster flag, defined as follows: 1 = source potentially falls within 1Mpc of known target cluster center; 0 = source does not fall within 1Mpc of target cluster center. Note (5): Optical ID flag, defined as follows: 6 = non-detection but near bright source (limiting mag will be incorrect) 5 = unclear which source is optical counterpart 4 = near bright source (magnitude affected) 3 = bright source - magnitude taken from Guide Star Catalog II 2 = upper limit 1 = optical identification 0 = no optical coverage Note (6): The flag on Rcmag has the following meaning: 1 = Rcmag>Rclim 0 = Rcmag<Rclim Note (7): SExtractor stellarity fraction range from 0.0 to 1.0: 0.0 = significantly extended source 1.0 = source consistent with perfectly stellar PSF
History: From electronic version of the journal References: Harrison et al., Paper I 2003ApJ...596..944H, Cat. J/ApJ/596/944
(End) Greg Schwarz [AAS], Marianne Brouty [CDS] 17-May-2005
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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