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 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 2003ApJ...596..944H, Cat. J/ApJ/596/944
(End) Greg Schwarz [AAS], Marianne Brouty [CDS] 17-May-2005