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J/ApJ/664/53    UV photometry of GALEX QSO candidates             (Atlee+, 2007)

Photometric selection of QSO candidates from GALEX sources. Atlee D.W., Gould A. <Astrophys. J., 664, 53-63 (2007)> =2007ApJ...664...53A
ADC_Keywords: QSOs ; Ultraviolet Keywords: quasars: general Abstract: We present a catalog of 36120 QSO candidates from the Galaxy Evolution Explorer (GALEX) Release Two (GR2) UV catalog and the USNO-A2.0 optical catalog. The selection criteria are established using known quasars from the Sloan Digital Sky Survey (SDSS). The SDSS sample is then used to assign individual probabilities to our GALEX USNO candidates. The mean probability is ∼50% and would rise to ∼65% if better morphological information than that from USNO were available to eliminate galaxies. The sample is ∼40% complete for i≤19.1. Candidates are cross identified in 2MASS, FIRST, SDSS, and the XMM-Newton Slewing Survey (XMMSL1), whenever such counterparts exist. The present catalog covers the 8000deg2 of GR2 lying above |b|=25°, but can be extended to all 24000deg2 that satisfy this criterion as new GALEX data become available. Description: GALEX records magnitudes in two bandpasses, the far-UV (FUV) and near-UV (NUV) filters. The FUV filter is characterized by λeff=1528Å, with a range of 1344-1786Å; the NUV filter has λeff=2271Å, with a range of 1771-2831Å. We select QSO candidates from GALEX GR2, which includes 7077 GALEX AIS pointings covering approximately 8000deg2 on the sky (http://galex.stsci.edu/GR2/)as well as ∼350 Medium Imaging Survey (MIS) and ∼100 Deep Imaging Survey (DIS) pointings. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table2.dat 144 36120 Catalog of QSO candidates table5.dat 112 80 Candidates for spectroscopy with additional photometric or spectroscopic information from SDSS DR5
See also: I/252 : The USNO-A2.0 Catalogue (Monet+ 1998) II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003) VII/248 : Quasars and Active Galactic Nuclei (12th Ed.) (Veron+ 2006) J/A+A/480/611 : XMM-Newton slew survey catalogue, XMMSL1 (Saxton+, 2008) J/ApJS/173/185 : GALEX ultraviolet atlas of nearby galaxies (Gil de Paz+, 2007) http://galex.stsci.edu/GR2 : GALEX Home Page Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 13 A13 --- USNO The USNO-A2.0 (Cat. I/252) identifier 15- 33 A19 --- GALEX The GALEX identifier 35- 43 F9.5 deg RAdeg Right Ascension in decimal degrees (J2000) 45- 53 F9.5 deg DEdeg Declination in decimal degrees (J2000) 55- 57 I3 arcsec dRA Difference between USNO-A2.0 & GALEX Right Ascension 59- 61 I3 arcsec dDe Difference between USNO-A2.0 & GALEX Declination 63- 66 F4.1 mag Bmag USNO-A2.0 (I/252) Blue plate magnitude (1) 68- 72 F5.1 --- S/G-B USNO-A2.0 (I/252) Blue plate separator 74- 77 F4.1 mag Rmag USNO-A2.0 (I/252) Red plate magnitude (1) 79- 83 F5.1 --- S/G-R USNO-A2.0 (I/252) Red plate separator 85- 89 F5.2 mag FUVmag GALEX FUV-band magnitude (135-175nm) 91- 94 F4.2 mag e_FUVmag The 1σ error in FUVmag 96-100 F5.2 mag NUVmag GALEX NUV-band magnitude (175-280nm) 102-105 F4.2 mag e_NUVmag The 1σ error in NUVmag 107-112 F6.1 mas/yr pmRA Proper motion in Right Ascension 114-119 F6.1 mas/yr pmDE Proper motion in Declination 121-123 A3 --- Var Source variable ? 125 I1 --- SDSS SDSS flag (2) 127-130 A4 --- Match Other catalog match flag (3) 132-137 F6.4 --- ExPr Probability of having extended morphology 139-144 F6.4 --- QPr Conditional probability of being QSO if a point source
Note (1): We find that USNO photometry is accurate to ∼0.35mag. Note (2): SDSS flags as follows: 0 = Candidate not matched to SDSS DR4 1 = SDSS Spectroscopic QSO 2 = SDSS Spectroscopic Object, non QSO 3 = SDSS Point Source in SDSS QSO Selection Area 4 = SDSS Point Source Outside Selection Area 5 = SDSS Extended Source Note (3): Catalog match flags as follows: V = Veron, Cat. VII/248 M = 2MASS, Cat. II/246 F = FIRST, Cat. VIII/71 X = XMMSL1, Cat. J/A+A/480/611
Byte-by-byte Description of file: table5.dat
Bytes Format Units Label Explanations
1- 13 A13 --- USNO The USNO-A2.0 (Cat. I/252) identifier 15- 33 A19 --- GALEX The GALEX identifier 35- 43 F9.5 deg RAdeg Right Ascension in decimal degrees (J2000) 45- 53 F9.5 deg DEdeg Declination in decimal degrees (J2000) 55- 58 F4.1 mag Bmag USNO-A2.0 Blue plate magnitude 60- 63 F4.1 mag Rmag USNO-A2.0 Red plate magnitude 65- 71 F7.4 mag FUVmag GALEX FUV-band magnitude 73- 79 F7.4 mag NUVmag GALEX NUV-band magnitude 81- 86 F6.4 --- ExPr Probability of having extended morphology 88- 93 F6.4 --- QPr Conditional probability of being QSO if a point source (1) 95-112 A18 --- ID Source identification (2)
Note (1): Candidates are listed in order of decreasing conditional probability. Note (2): Candidates marked "target" were selected by SDSS as potential QSOs, but have no DR5 spectroscopy.
History: From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 19-Aug-2009
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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