J/ApJS/150/19 ChaMP. I. First X-ray source catalog (Kim+, 2004)
Chandra Multiwavelength Project. I. First X-ray source catalog.
Kim D.-W., Cameron R.A., Drake J.J., Evans N.R., Freeman P., Gaetz T.J.,
Ghosh H., Green P.J., Harnden F.R.Jr, Karovska M., Kashyap V., Maksym P.W.,
Ratzlaff P.W., Schlegel E.M., Silverman J.D., Tananbaum H.D.,
Vikhlinin A.A., Wilkes B.J., Grimes J.P.
<Astrophys. J. Suppl. Ser., 150, 19 (2004)>
=2004ApJS..150...19K 2004ApJS..150...19K
ADC_Keywords: Surveys ; X-ray sources
Keywords: surveys - X-rays: general
Abstract:
The Chandra Multiwavelength Project (ChaMP) is a wide-area (∼14deg2)
survey of serendipitous Chandra X-ray sources, aiming to establish
fair statistical samples covering a wide range of characteristics
(such as absorbed active galactic nuclei, high-z clusters of galaxies)
at flux levels (fX∼10-15 to 10-14erg/s/cm2) ) intermediate
between the Chandra deep surveys and previous missions. We present the
first ChaMP catalog, which consists of 991 near on-axis, bright X-ray
sources obtained from the initial sample of 62 observations. The data
have been uniformly reduced and analyzed with techniques specifically
developed for the ChaMP and then validated by visual examination. To
assess source reliability and positional uncertainty, we perform a
series of simulations and also use Chandra data to complement the
simulation study. The false source detection rate is found to be as
good as or better than expected for a given limiting threshold. On the
other hand, the chance of missing a real source is rather complex,
depending on the source counts, off-axis distance (or PSF), and
background rate. The positional error (95% confidence level) is
usually less than 1" for a bright source, regardless of its off-axis
distance, while it can be as large as 4" for a weak source (∼20counts)
at a large off-axis distance (Doff-axis>8'). We have also developed
new methods to find spatially extended or temporary variable sources,
and those sources are listed in the catalog.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table3.dat 79 19 Source Flags
table6.dat 107 102 Energy Conversion Factors
table7.dat 84 991 ChaMP X-ray Sources
table8.dat 134 991 X-ray Photometry
table9.dat 60 991 X-ray colors
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1 A1 --- Type [FXVO] Flag letter (1)
3- 5 I3 --- Flag Flag number
7- 80 A74 --- Com Meaning of the flag
--------------------------------------------------------------------------------
Note (1): Type of source as follows:
F = False X-Ray Sources
X = X-Ray Sources-Questionable
V = Valid Sources, but Source Properties May Be Subject to a
Large Uncertainty
O = Other Cases
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table6.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- ObsID ChaMP X-ray source identification number
6- 8 A3 --- CCDID The CCD identification number (1)
10- 15 F6.2 --- B-1.2 B energy conversion factor for Γ=1.2 (2)
17- 21 F5.2 --- S-1.2 S energy conversion factor for Γ=1.2 (2)
23- 28 F6.2 --- H-1.2 H energy conversion factor for Γ=1.2 (2)
30- 34 F5.2 --- Sc-1.2 Sc energy conversion factor for Γ=1.2 (2)
36- 41 F6.2 --- Hc-1.2 Hc energy conversion factor for Γ=1.2 (2)
43- 48 F6.2 --- B-1.4 B energy conversion factor for Γ=1.4 (2)
50- 54 F5.2 --- S-1.4 S energy conversion factor for Γ=1.4 (2)
56- 61 F6.2 --- H-1.4 H energy conversion factor for Γ=1.4 (2)
63- 67 F5.2 --- Sc-1.4 Sc energy conversion factor for Γ=1.4 (2)
69- 74 F6.2 --- Hc-1.4 Hc energy conversion factor for Γ=1.4 (2)
76- 81 F6.2 --- B-1.7 B energy conversion factor for Γ=1.7 (2)
83- 87 F5.2 --- S-1.7 S energy conversion factor for Γ=1.7 (2)
89- 94 F6.2 --- H-1.7 H energy conversion factor for Γ=1.7 (2)
96-100 F5.2 --- Sc-1.7 Sc energy conversion factor for Γ=1.7 (2)
102-107 F6.2 --- Hc-1.7 Hc energy conversion factor for Γ=1.7 (2)
--------------------------------------------------------------------------------
Note (1): 0-3 for ACIS-I and 4-9 for ACIS-S.
Note (2): Energy Conversion Factors (10-13erg/s/cm2 per 1ct/s) are
calculated in the following energy bands:
B = counts in 0.3-8.0keV and flux in 0.3-8.0keV;
S = counts in 0.3-2.5keV and flux in 0.5-2.0keV;
H = counts in 2.5-8.0keV and flux in 2.0-8.0keV;
Sc = counts in 0.5-2.0keV and flux in 0.5-2.0keV;
Hc = counts in 2.0-8.0keV and flux in 2.0-8.0keV.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table7.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 5 A5 --- --- [CXOMP]
7- 22 A16 --- CXOMP ChaMP source position name in J2000
24- 27 I4 --- ObsID ChaMP X-ray source identification number
29 I1 --- CCDID The CCD identification number (1)
31- 33 I3 --- SNum Source number assigned by wavdetect
35- 44 F10.6 deg RAdeg Right Ascension in decimal degrees (J2000)
46- 55 F10.6 deg DEdeg Declination in decimal degrees (J2000)
57- 59 F3.1 arcsec ePos Positional error (see section 5)
61- 64 F4.1 arcmin Doff The off-axis distance
66- 69 F4.1 arcsec Rad Source extraction radius (see section 3.3) (2)
71- 76 F6.2 ks EExp Effective exposure
78- 80 I3 --- Flag1 ? Source flag (see table3.dat and section 3.5)
82- 84 I3 --- Flag2 ? Source flag (see table3.dat and section 3.5)
--------------------------------------------------------------------------------
Note (1): 0-3 for ACIS-I and 4-9 for ACIS-S
Note (2): We choose the source extraction radius to be a 95% encircled
energy radius (at 1.5keV) as a function of off-axis angle (determined
from the "psfsize" table, psfsize_2000830.fits, available in the CIAO
and CALDB public distribution) with a minimum of 3" near the aim point
and a maximum of 40" at the far edge of the field of view.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table8.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 5 A5 --- --- [CXOMP]
7- 22 A16 --- CXOMP ChaMP source position name in J2000
24- 31 F8.2 ct BNet Net 0.3-8.0keV counts (1)
33- 38 F6.2 ct e_BNet Error in BNet
40- 47 F8.2 ct S1Net Net 0.3-0.9keV counts (1)
49- 54 F6.2 ct e_S1Net Error in S1Net
56- 63 F8.2 ct S2Net Net 0.9-2.5keV counts (1)
65- 70 F6.2 ct e_S2Net Error in S2Net
72- 79 F8.2 ct HNet Net 2.5-8.00keV counts (1)
81- 86 F6.2 ct e_HNet Error in HNet
88- 95 F8.2 ct ScNet Net 0.5-2.0keV counts (1)
97-102 F6.2 ct e_ScNet Error in ScNet
104-111 F8.2 ct HcNet Net 2.0-8.0keV counts (1)
113-118 F6.2 ct e_HcNet Error in HcNet
120-126 F7.3 10-16W/m2 BFlux The 0.3-8.0keV flux in units
of 10-13erg/s/cm2 (1)
128-133 F6.3 10-16W/m2 e_BFlux Error in BFlux
--------------------------------------------------------------------------------
Note (1): Source counts were extracted within a circle centered on the
wavdetect-determined source position and background counts are
extracted locally in an annulus surrounding the source. See section
3.3 for more details.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table9.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 5 A5 --- --- [CXOMP]
7- 22 A16 --- CXOMP ChaMP source position name in J2000
24- 28 F5.2 --- HR The Hardness Ratio, (H-S)/(H+S) (1)
30- 33 F4.2 --- e_HR Error in HR
35- 40 F6.2 --- C21 The C21 (log(S1/S2)) X-ray color (1) (2)
42- 46 F5.2 --- e_C21 Error in C21
48- 53 F6.2 --- C32 The C32 (log(S2/H)) X-ray color (1) (2)
55- 59 F5.2 --- e_C32 Error in C32
--------------------------------------------------------------------------------
Note (1): Where
H is the total count in the hard (2.5-8.0keV) band,
S is the total count in the soft (0.3-2.5keV) band,
S1 is the total count in the 0.3-0.9keV band,
S2 is the total count in the 0.9-2.5keV band.
Note (2): Note on X-ray colors as follows:
-99.00 = lower limit
99.00 = upper limit
999.00 = undetermined
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 23-Jan-2004