J/ApJS/180/102 AEGIS-X: Chandra deep survey (Laird+, 2009)
AEGIS-X: the Chandra Deep Survey of the Extended Groth Strip.
Laird E.S., Nandra K., Georgakakis A., Aird J.A., Barmby P.,
Conselice C.J., Coil A.L., Davis M., Faber S.M., Fazio G.G.,
Guhathakurta P., Koo D.C., Sarajedini V., Willmer C.N.A.
<Astrophys. J. Suppl. Ser., 180, 102-116 (2009)>
=2009ApJS..180..102L 2009ApJS..180..102L
ADC_Keywords: X-ray sources ; Surveys ; Cross identifications ; Photometry
Keywords: galaxies: active - galaxies: nuclei - surveys - X-rays: galaxies
Abstract:
We present the EGIS-X survey, a series of deep Chandra ACIS-I
observations of the Extended Groth Strip. The survey comprises
pointings at eight separate positions, each with nominal exposure of
200ks, covering a total area of approximately 0.67deg2 in a strip of
length 2 degrees. We describe in detail an updated version of our data
reduction and point-source-detection algorithms used to analyze these
data. A total of 1325 band-merged sources have been found to a Poisson
probability limit of 4x10-6, with limiting fluxes of 5.3x10-21W/m2
in the soft (0.5-2keV) band and 3.8x10-19W/m2 in the hard (2-10keV)
band. We present simulations verifying the validity of our
source-detection procedure and showing a very small, <1.5%,
contamination rate from spurious sources. Optical/NIR counterparts
have been identified from the DEEP2, CFHTLS, and Spitzer/Infrared
Array Camera (IRAC) surveys of the same region. Using a likelihood
ratio method, we find optical counterparts for 76% of our sources,
complete to RAB=24.1, and, of the 66% of the sources that have IRAC
coverage, 94% have a counterpart to a limit of 0.9uJy at 3.6um
(mAB=23.8). After accounting for (small) positional offsets in the
eight Chandra fields, the astrometric accuracy of Chandra positions is
found to be 0"8rms; however, this number depends both on the off-axis
angle and the number of detected counts for a given source. All data
products described in this paper are made available via a public Web
site.
Description:
The data used in this paper were obtained during two Chandra
observation cycles. An initial Chandra observation in the EGS region
was taken in 2002 August during Cycle 3. These observations of the
"Groth-Westphal Strip" (GWS) region have been reported by Nandra et
al. (2005, Cat. J/MNRAS/356/568). The majority of the AEGIS-X data
were obtained over the period 2005 March-December as part of Chandra
Cycle 6.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table9.dat 118 1325 Chandra AEGIS-X source catalog: basic source
properties
table10.dat 187 1325 Chandra AEGIS-X source catalog: source fluxes
and hardness ratios
table11.dat 109 1325 Optical and IR counterparts to the AEGIS-X sources
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See also:
B/chandra : The Chandra Archive Log (CXC, 1999-)
J/ApJS/177/431 : Mid-IR sources in EGS (Barmby+, 2008)
J/ApJ/642/126 : Mid-IR observations in the extended Groth strip
(Barmby+, 2006)
J/AJ/132/2159 : IRAC counterparts of 6cm galaxies in EGS (Willner+, 2006)
J/ApJ/625/6 : Galaxy groups in the DEEP2 Galaxy Redshift Survey
(Gerke+, 2005)
J/MNRAS/356/568 : Deep Chandra survey of the Groth Strip (Nandra+, 2005)
J/MNRAS/371/221 : Deep Chandra survey of the Groth Strip. II.
(Georgakakis+, 2006)
http://terapix.iap.fr/rubrique.php?id_rubrique=169 : CFHTLS data releases
http://deep.berkeley.edu/ : DEEP2 redshift survey Home Page
Byte-by-byte Description of file: table9.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- --- [egs_] (Extended Groth Strip)
5- 8 I4 --- egs [1,1325] Source ID (G1)
10- 12 A3 --- --- [egs]
13- 17 A5 --- Field Field ID identifying individual field in
which the source was detected
19- 34 A16 --- CXOEGS CXO Object name (JHHMMSS.s+DDMMSS)
36- 45 F10.6 deg RAdeg X-ray Right Ascension in decimal degrees
(J2000)
47- 55 F9.6 deg DEdeg X-ray Declination in decimal degrees (J2000)
57- 60 F4.2 arcsec e_Pos Positional error
62- 66 F5.2 arcmin OAA Off-axis angle
68- 71 I4 ct Fcts Full (0.5-7keV) band, total counts
73- 76 F4.1 ct Fbkg Full (0.5-7keV) band, background cts
78- 81 I4 ct Scts Soft (0.5-2keV) band, total counts
83- 86 F4.1 ct Sbkg Soft (0.5-2keV) band, background cts
88- 91 I4 ct Hcts Hard (2-7keV) band, total counts
93- 96 F4.1 ct Hbkg Hard (2-7keV) band, background cts
98-100 I3 ct Ucts Ultra hard (4-7keV) band, total counts
102-105 F4.1 ct Ubkg Ultra hard (4-7keV) band, background cts
107-110 A4 --- Band Band(s) in which source is detected (1)
112-118 E7.2 --- badProb Lowest false detection probability found for
the four bands
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Note (1): Band is:
f = Full band (0.5-7keV);
s = Soft band (0.5-2keV);
h = Hard band (2-7keV);
u = Ultra hard band (4-7keV).
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Byte-by-byte Description of file: table10.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- --- [egs_] (Extended Groth Strip)
5- 8 I4 --- egs [1,1325] Source ID (G1)
10 A1 --- n_egs [a] Note about Bayesian fluxes (1)
12 A1 --- l_FBay Limit flag on FBBay
14- 19 F6.2 aW/m2 FBay Bayesian method full band (0.5-10keV) flux
21- 24 F4.2 aW/m2 E_FBay ? Upper 1σ error in FBBay
26- 29 F4.2 aW/m2 e_FBay ? Lower 1σ error in FBBay
31 A1 --- l_SBay Limit flag on SBBay
33- 38 F6.2 aW/m2 SBay Bayesian method soft band (0.5-2keV) flux
40- 43 F4.2 aW/m2 E_SBay ? Upper 1σ error in SBBay
45- 48 F4.2 aW/m2 e_SBay ? Lower 1σ error in SBBay
50 A1 --- l_HBay Limit flag on HBBay
52- 57 F6.2 aW/m2 HBay Bayesian method hard band (2-10keV) flux
59- 62 F4.2 aW/m2 E_HBay ? Upper 1σ error in HBBay
64- 67 F4.2 aW/m2 e_HBay ? Lower 1σ error in HBBay
69 A1 --- l_UBay Limit flag on UBBay
71- 76 F6.2 aW/m2 UBay Bayesian method ultra hard band (5-10keV) flux
78- 81 F4.2 aW/m2 E_UBay ? Upper 1σ error in UBBay
83- 86 F4.2 aW/m2 e_UBay ? Lower 1σ error in UBBay
88 A1 --- l_Fclas Limit flag on FBclas
90- 95 F6.2 aW/m2 Fclas Classical method full band (0.5-10keV) flux (2)
97-100 F4.2 aW/m2 E_Fclas ? Upper 1σ error in FBclas (2)
102-105 F4.2 aW/m2 e_Fclas ? Lower 1σ error in FBclas
107 A1 --- l_Sclas Limit flag on SBclas
109-114 F6.2 aW/m2 Sclas Classical method soft band (0.5-2keV) flux (2)
116-119 F4.2 aW/m2 E_Sclas ? Upper 1σ error in SBclas (2)
121-124 F4.2 aW/m2 e_Sclas ? Lower 1σ error in SBclas
126 A1 --- l_Hclas Limit flag on HBclas
128-133 F6.2 aW/m2 Hclas Classical method hard band (2-10keV) flux (2)
135-138 F4.2 aW/m2 E_Hclas ? Upper 1σ error in HBclas (2)
140-143 F4.2 aW/m2 e_Hclas ? Lower 1σ error in HBclas
145 A1 --- l_Uclas Limit flag on UBclas
147-152 F6.2 aW/m2 Uclas Classical method ultra hard band (5-10keV) flux
154-157 F4.2 aW/m2 E_Uclas ? Upper 1σ error in UBclas (2)
159-162 F4.2 aW/m2 e_Uclas ? Lower 1σ error in UBclas
164-168 F5.2 --- HRb Hardness ratio (HR) using Bayesian method
170-173 F4.2 --- E_HRb Upper 1σ error in HR-Bay
175-178 F4.2 --- e_HRb Lower 1σ error in HR-Bay
180-184 F5.2 --- HRc ?=-9.99 Hardness ratio using classical method
187 I1 --- Q [0/2] Photometry quality flag (3)
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Note (1): a = Bayesian fluxes in the detected bands were calculated from
70% EEF (Enclosed Energy Fraction).
Note (2): or 99% upper limit if the lower 1σ column (e_Xclas) is blank.
Unit is 10-15erg/cm2/s = 10-18W/m2
Note (3): Photometry quality flag as follows:
1 = the presence of a nearby source that may be contaminating the photometry
2 = another source was detected with the 90% EEF and that the photometry is
likely heavily contaminated and the source position uncertain.
0 = All other sources (OK).
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Byte-by-byte Description of file: table11.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- --- [egs_] (Extended Groth Strip)
5- 8 I4 --- egs [1,1325] Source ID (G1)
10 A1 --- f_egs ? [ab] Flag for source matching details (1)
12 A1 --- l_Rmag ? Limit flag on Rmag
14- 18 F5.2 mag Rmag ? DEEP2 R-band AB magnitude
20- 23 F4.2 arcsec DEEP2-X ? DEEP2 optical and X-ray position offset
25- 30 F6.2 --- LR-DEEP2 ? Likelihood ratio for DEEP2 counterpart
32- 39 I8 --- DEEP2-ID ? DEEP2 source ID, (2)
41 A1 --- l_imag ? Limit flag on i' mag
43- 47 F5.2 mag imag ? CFHTLS i'-band AB magnitude
49- 52 F4.2 arcsec CFHT-X ? CFHTLS optical and X-ray position offset
54- 59 F6.2 --- LR-CFHT ? Likelihood ratio for CFHTLS counterpart
61- 69 A9 --- CFHT-ID ? CFHTLS source ID (3)
71 A1 --- l_3.6mag ? Limit flag on IRAC 3.6micron mag
73- 77 F5.2 mag 3.6mag ? IRAC 3.6micron AB magnitude
79- 82 F4.2 arcsec IRAC-X ? IRAC 3.6micron and X-ray position offset
84- 89 F6.2 --- LR-IRAC ? Likelihood ratio for IRAC 3.6micron
counterpart
91-109 A19 --- EGSIRAC ? IRAC 3.6micron source ID
(JHHMMSS.ss+DDMMSS.s) (4)
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Note (1): Flag as follows:
a = Bright, resolved galaxies that are clearly present in the CFHTLS i'
imaging but have been excluded from CFHTLS catalog for unknown reason.
b = Bright IRAC sources, without secure optical counterpart listed in the
table, that have been excluded from Figure 9. Clear, very bright optical
counterparts exist, but are excluded from DEEP2 catalog.
Note (2): DEEP2 optical photometry catalog reference: Coil et al.,
2004ApJ...617..765C 2004ApJ...617..765C.
Note (3): CFHT Legacy Survey (CFHTLS) T0003 release catalog reference:
http://terapix.iap.fr/article.php?id_article=556
Note (4): IRAC catalog reference: Barmby et al., 2008, Cat. J/ApJS/177/431
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Global Notes:
Note (G1): Sources are listed in order of increasing right ascension.
<[LNG2009] egs-NNNN> in Simbad.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 06-Oct-2009