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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
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:
FileName Lrecl Records Explanations
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
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
Bytes Format Units Label Explanations
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)
Note (1): Offset from the nominal pointing direction.
Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
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 K_s_ 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
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.
Byte-by-byte Description of file: table3.dat
Bytes Format Units Label Explanations
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 ? Lambda rest-frame absolute B magnitude (1) 36- 40 F5.2 [solLum] log(L0.5-2keV)L ? Lambda 0.5-2keV band luminosity (1) 42- 46 F5.2 [solLum] log(L2-10keV)L ? Lambda 2-10keV band luminosity (1) 48- 67 A20 --- Class Galaxy class or spectral type for stars
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
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
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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