J/AJ/123/2223 SPICES II: CHANDRA observations of Lynx (Stern+, 2002)
SPICES II: optical and near-infrared identifications of faint X-ray sources
from deep CHANDRA observations of Lynx.
Stern D., Tozzi P., Stanford S.A., Rosati P., Holden B., Eisenhardt P.,
Elston R., Wu K.L., Connolly A., Spinrad H., Dawson S., Dey A., Chaffee F.H.
<Astron. J. 123, 2223 (2002)>
=2002AJ....123.2223S 2002AJ....123.2223S
ADC_Keywords: Surveys ; X-ray sources ; Galaxy catalogs ; Galaxies, photometry
Mission_Name: Chandra
Keywords: cosmology: observations - diffuse radiation - galaxies: active -
surveys - X-rays
Abstract:
We present our first results on field X-ray sources detected in a
deep, 184.7ks observation with the Advanced CCD Imaging Spectrometer
(ACIS-I) on the Chandra X-Ray Observatory. The observations target the
Lynx field (RA=08h48min, DE=+44°54') of SPICES, the Spectroscopic
Photometric Infrared-Chosen Extragalactic Survey, which contains three
known X-ray-emitting clusters at redshifts of z=0.57, 1.26, and 1.27.
Not including the known clusters, in the 17'x17' ACIS-I field we
detect 132 sources in the 0.5-2keV (soft) X-ray band down to a
limiting flux of ∼1.7x10-16ergs/cm2/s and 11 sources in the
2-10keV (hard) X-ray band down to a limiting flux of
∼1.3x10-15ergs/cm2/s. The combined catalog contains a total of 153
sources, of which 42 are detected only in the soft band and 21 are
detected only in the hard band.
Confirming previous Chandra results, we find that the fainter sources
have harder X-ray spectra, providing a consistent solution to the
long-standing "spectral paradox." From deep optical and near-infrared
follow-up data, 77% of the X-ray sources have optical counterparts to
I=24, and 71% of the X-ray sources have near-infrared counterparts to
Ks=20. Four of the 24 sources in the near-IR field are associated with
extremely red objects (EROs; I-Ks≥4). We have obtained spectroscopic
redshifts with the Keck telescopes of 18 of the Lynx Chandra sources.
These sources comprise a mix of broad-lined active galaxies,
apparently normal galaxies, and two late-type Galactic dwarfs.
Intriguingly, one Galactic source is identified with an M7 dwarf
exhibiting nontransient, hard X-ray emission. Thirteen of the Chandra
sources are located within regions for which we have Hubble Space
Telescope imaging. Nine of the sources are detected, showing a range
of morphologies: several show compact cores embedded within diffuse
emission, while others are spatially extended showing typical galaxy
morphologies. Two of the Chandra sources in this subsample appear to
be associated with mergers. We briefly review non-active galactic
nucleus mechanisms to produce X-ray emission and discuss properties of
the Lynx Chandra sample in relation to other samples of X-ray and
non-X-ray sources.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 85 153 X-ray source properties
table2.dat 93 106 Optical/Near-IR Properties of X-Ray Sources
table3.dat 67 18 Luminosities of X-ray sources
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See also:
B/chandra : The Chandra Archive Log (CXC, 2002)
J/A+A/379/740 : ESO Imaging Survey (EIS) (Arnouts+, 2001)
J/A+AS/71/221 : The 65W part of the WSRT 21 cm survey in Lynx (Oort, 1987)
J/A+AS/73/103 : The 64W part of the WSRT 92 cm survey in Lynx (Oort, 1988)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- [STS2002] Sequential number
5- 6 I2 h RAh Right ascension (J2000.0)
8- 9 I2 min RAm Right ascension (J2000.0)
11- 15 F5.2 s RAs Right ascension (J2000.0)
17 A1 --- DE- Declination sign (J2000.0)
18- 19 I2 deg DEd Declination (J2000.0)
21- 22 I2 arcmin DEm Declination (J2000.0)
24- 27 F4.1 arcsec DEs Declination (J2000.0)
29- 35 F7.2 ct Scounts ? Counts in the soft band (0.5-2keV)
37- 41 F5.2 ct e_Scounts ? rms uncertainty on Scounts
43- 48 F6.2 ct Hcounts ? Counts in the hard band (2-7keV)
50- 54 F5.2 ct e_Hcounts ? rms uncertainty on Hcounts
56- 60 F5.2 --- HR ? Hardness ratio (H-S)/(H+S)
62- 65 F4.1 --- S/N Signal-to-noise ratio of the X-ray detection
67- 71 F5.2 arcmin Dist Off-axis angle of the X-ray source (1)
73- 78 F6.2 10-18W/m2 S0.5-2keV ? Flux in the soft band (0.5-2keV)
80- 85 F6.2 10-18W/m2 S2-10keV ? Flux in the hard band (2-10keV)
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Note (1): Offset from the nominal pointing direction.
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- [STS2002] Source identification number
5 A1 --- f_[STS2002] [a] Flag on [STS2002] (1)
8- 12 F5.2 arcsec oRA ? X-ray minus optical right ascension offset
14 A1 --- f_oRA [u] Indicates undetected source
16- 20 F5.2 arcsec oDE ? X-ray minus optical declination offset
22 A1 --- f_oDE [u] Indicates undetected source
24- 28 F5.2 mag Bmag ? The Harris B band magnitude (3)
30 A1 --- f_Bmag [u] Indicates undetected source
32- 36 F5.2 mag Rmag ? The Harris R band magnitude (3)
38 A1 --- f_Rmag [u] Indicates undetected source
40 A1 --- u_Rmag [:] Indicates Rmag somewhat affected by nearby
stellar bleed trail
42- 46 F5.2 mag Imag ? The Harris I band magnitude (3)
48 A1 --- f_Imag [u] Indicates undetected source
50- 54 F5.2 mag zmag ? The RG850 long-pass z band magnitude
56 A1 --- f_zmag [u] Indicates undetected source
58- 62 F5.2 mag Jmag ? The J band magnitude (4)
64 A1 --- f_Jmag [u] Indicates undetected source
66- 70 F5.2 mag Ksmag ? The Ks band magnitude (4)
72 A1 --- f_Ksmag [u] Indicates undetected source
74- 78 F5.3 --- z ? Spectroscopic redshift
80 A1 --- f_z [u] Indicates undetected source
82- 93 A12 --- SID The SPICES identification
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Note (1): Indicates host is more than 1.5" away from faint X-ray source.
Note (3): Sources with bad photometry, due either to source saturation or
contamination from the stellar bleed trail of a nearby, bright source,
are listed as 99.00.
The Harris passbands are:
B-band: λc = 431.3nm Dλ = 106.9nm
R-band: λc = 645.8nm Dλ = 147.2nm
I-band: λc = 820.4nm Dλ = 182.1nm
Note (4): Only those sources contained within the near-infrared field are
tabulated under the near-infrared photometry columns. Sources with bad
photometry, due either to source saturation or contamination from the
stellar bleed trail of a nearby, bright source, are listed as 99.00.
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- [STS2002] Sequential number
5- 9 F5.3 ---- z Redshift
12- 16 F5.1 mag BMAG:E ? EdS rest-frame absolute B magnitude (1)
18- 22 F5.2 [solLum] log(L0.5-2keV)E ? EdS 0.5-2keV band luminosity (1)
24- 28 F5.2 [solLum] log(L2-10keV)E ? EdS 2-10keV band luminosity (1)
30- 34 F5.1 mag BMAG:L ? Λ rest-frame absolute B
magnitude (1)
36- 40 F5.2 [solLum] log(L0.5-2keV)L ? Λ 0.5-2keV band luminosity (1)
42- 46 F5.2 [solLum] log(L2-10keV)L ? Λ 2-10keV band luminosity (1)
48- 67 A20 --- Class Galaxy class or spectral type for stars
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Note (1): We adopt Γ=1.4 for calculation of X-ray k-corrections.
EdS: Einstein-de Sitter universe with
H0=50km/s/Mpc, ΩM=1, ΩΛ=0
Λ: dark energy cosmology with
H0=65km/s/Mpc, ΩM=0.35, ΩΛ=0.65
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History:
* 30-May-2002: From electronic version of the journal
* 05-Jun-2007: Some units and label corrections made in this file (ReadMe)
(thanks to Steve Drake, NASA)
(End) Greg Schwarz [AAS], Patricia Bauer [CDS] 30-May-2002