J/AJ/127/213 LALA Bootes field X-ray source catalog (Wang+, 2004)
The 172 ks Chandra exposure of the LALA Bootes field: X-ray source catalog.
Wang J.X., Malhotra S., Rhoads J.E., Brown M.J.I., Dey A., Heckman T.M.,
Jannuzi B.T., Norman C.A., Tiede G.P., Tozzi P.
<Astron. J., 127, 213-229 (2004)>
=2004AJ....127..213W 2004AJ....127..213W
ADC_Keywords: X-ray sources ; Surveys ; Magnitudes
Mission_Name: Chandra
Keywords: catalogs - galaxies: active - galaxies: high-redshift -
X-rays: diffuse background - X-rays: galaxies
Abstract:
We present an analysis of a deep, 172ks Chandra observation of the
Large Area Lyman Alpha survey (LALA) Bootes field, obtained with the
Advanced CCD Imaging Spectrometer (ACIS-I) on board the Chandra X-Ray
Observatory. This is one of the deepest Chandra images of the
extragalactic sky; only the 2Ms Chandra Deep Field North (CDF-N) and
1Ms Chandra Deep Field South (CDF-S) are substantially deeper. In
this paper we present the X-ray source catalog obtained from this
image, along with an analysis of source counts and optical
identifications. The X-ray image is composed of two individual
observations obtained in 2002 and reaches 0.5-2.0 and 2.0-10.0keV flux
limits of 1.5x10-16 and 1.0x10-15ergs/cm2/s, respectively, for
point sources near the aim point. A total of 168 X-ray sources were
detected: 160 in the 0.5-7.0keV band, 132 in the 0.5-2.0keV band, and
111 in the 2.0-7.0keV band.
Our primary optical data are R-band imaging from the NOAO Deep
Wide-Field Survey (NDWFS), with a limiting magnitude of R=25.7 (Vega,
3σ, and 4" diameter aperture).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 190 169 CHANDRA Sources in LALA Bootes Field
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See also:
B/chandra : The Chandra Archive Log (CXC, 2002-)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- [WMR2004] Source identification number
5- 12 A8 --- --- [CXOLALA1]
14- 29 A16 --- CXOLALA1 IAU Name (based on J2000 position)
31- 32 I2 h RAh Hour of Right Ascension (J2000) (1)
34- 35 I2 min RAm Minute of Right Ascension (J2000) (1)
37- 41 F5.2 s RAs Second of Right Ascension (J2000) (1)
42 A1 --- DE- Sign of declination (J2000) (1)
43- 44 I2 deg DEd Degree of Declination (J2000) (1)
46- 47 I2 arcmin DEm Arcminute of Declination (J2000) (1)
49- 52 F4.1 arcsec DEs Arcsecond of Declination (J2000) (1)
54- 56 F3.1 arcsec PosErr The 3σ centroid position uncertainty
58- 63 F6.1 ct TCts Net total (0.5-7.0keV) counts (2)
65- 68 F4.1 ct E_TCts Upper 1σ Poisson uncertainty in TCts
70- 73 F4.1 ct e_TCts Lower 1σ Poisson uncertainty in TCts
75- 80 F6.1 ct SCts Net soft (0.5-2.0keV) counts (2)
82- 85 F4.1 ct E_SCts Upper 1σ Poisson uncertainty in SCts
87- 90 F4.1 ct e_SCts Lower 1σ Poisson uncertainty in SCts
92- 97 F6.1 ct HCts Net hard (2.0-7.0keV) counts(2)
99-102 F4.1 ct E_HCts Upper 1σ Poisson uncertainty in HCts
104-107 F4.1 ct e_HCts Lower 1σ Poisson uncertainty in HCts
109-111 A3 --- Det Band of source detection (3)
113-117 F5.2 --- HR Hardness ratio (4)
119-122 F4.2 --- E_HR Upper 1σ Poisson uncertainty in HR
124-127 F4.2 --- e_HR Lower 1σ Poisson uncertainty in HR
129-134 F6.2 10-18W/m2 S0.5-10 The 0.5-10 keV Xray flux (5)
136 A1 --- l_S0.5-2 Limit flag on S0.5-2
137-142 F6.2 10-18W/m2 S0.5-2 The 0.5-2 keV Xray flux (5)
144 A1 --- l_S2-10 Limit flag on S2-10
145-150 F6.2 10-18W/m2 S2-10 The 2-10 keV Xray flux (5)
152-155 F4.1 arcsec oRA ? Optical counterpart Right Ascension
offset from the Xray position (6)
157-160 F4.1 arcsec oDE ? Optical counterpart Declination offset
from the Xray position (6)
162 A1 --- l_Rmag The 3σ limit flag on Rmag
163-167 F5.2 mag Rmag ? The R band AUTO magnitude (7)
169-172 F4.2 mag e_Rmag ? The 1σ Uncertainty in Rmag
174 A1 --- f_Rmag [ab] Flag on Rmag (8)
176-178 F3.1 arcsec FWHM ? Optical counterpart Full-Width
Half-Maximum in R band image
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Note (1): The positions were determined by WAVDETECT.
Whenever possible, we use positions derived in the soft band, which
has the best spatial resolution among the three bands. For sources
which are not detected in the soft band, we use total band positions
instead if available, and hard band positions were quoted for those
sources detected only in the hard band.
Note (2): The counts were calculated using circular aperture photometry.
For each source, we defined a source region which is a circle centered
on the position, with radius Rs set to the 95% encircled-energy
radius of Chandra ACIS PSF at the source position. Rs varies in the
range of 2" to 15" from the center to the edge of the field. Source
photons were then extracted from the regions, and the local background
was extracted from an annulus with outer radius of 2.4*Rs and inner
radius of 1.2*Rs, after masking out nearby sources. The aperture
correction (*1/0.95) was applied to the source counts.
Note (3): Multiple letters are used for sources detected in more than one band.
T = source detected in total band;
S = source detected in soft band;
H = source detected in hard band.
Note (4): Where HR=(H-S)/(H+S), where H and S are the vignetting-corrected
net counts in the hard and soft band respectively. The hardness ratios
vs 0.5-10.0keV band Xray fluxes for the detected X-ray sources are
plotted in Fig. 2. Assuming a power-law spectrum with the Galactic HI
column density (1.15*1020cm-2), the observed hardness ratio can be
converted to the photon index Γ of the spectrum, which is also
presented in the figure.
Note (5): In units of 1015erg/s/cm2 and Galactic absorption corrected.
A power-law spectrum with the Galactic column density was assumed to
calculate the conversion factors from net counts to X-ray fluxes. See
text for additional details.
Note (6): Where oRA=RAR-RAX and oDE=DER-DEX.
Note (7): Kron-like elliptical aperture magnitudes (Bertin & Arnouts,
1996A&AS..117..393B 1996A&AS..117..393B). The uncertainties are direct output from
SExtractor, without including the uncertainty of the R-band zeropoint.
For sources which are not detected in R-band, 3σ upper limits of
the magnitudes are given when available.
Note (8): Flags on Rmag are:
a: Source No. 22 is overlapped by bleeding of charge in the NDWFS R
image we used in this paper. Source position and R band magnitude
were measured from an older version of the NDWFS R image.
b: Source No. 37 and 160 are overlapped by bleeding of charge in both
the NDWFS R and the older NDWFS R images.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 20-Feb-2004