J/MNRAS/405/2062 AGN candidates from 2MASS/ROSAT catalogs (Kouzuma+, 2010)
Properties of near-infrared-selected AGN candidates with 2MASS/ROSAT catalogues.
Kouzuma S., Yamaoka H.
<Mon. Not. R. Astron. Soc., 405, 2062-2068 (2010)>
=2010MNRAS.405.2062K 2010MNRAS.405.2062K
ADC_Keywords: Active gal. nuclei ; QSOs ; Radio sources ; Infrared sources
Keywords: catalogs ; galaxies: active ; quasars: general
Abstract:
We report on the near-infrared-selected active galactic nuclei (AGN)
candidates extracted from Two Micron All Sky Survey (2MASS)/ROSAT
catalogues and discuss their properties. First, near-infrared
counterparts of an X-ray source in ROSAT catalogues [namely bright
source catalogue (BSC, Cat. IX/10) and faint source catalogue (FSC,
Cat. IX/29)] were extracted by positional cross-identification of
≤30arcsec. As these counterparts would contain many
mis-identifications, we further imposed near-infrared colour selection
criteria and extracted reliable AGN candidates (BSC: 5273, FSC:
10071). Of the 5273 (10071) candidates in the BSC (FSC), 2053 (1008)
are known AGNs. Near-infrared and X-ray properties of candidates show
similar properties with known AGNs and are consistent with the
previous studies. We also searched for counterparts in other
wavelengths (i.e. optical, near-infrared and radio) and investigated
properties in multiwavelength. No significant difference between known
AGNs and unclassified sources could be seen. However, some
unclassified sources in the FSC showed slightly different properties
compared with known AGNs. Consequently, it is highly probable that we
could extract reliable AGN candidates, though candidates in the FSC
might be spurious.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
bsc_k.dat 110 2053 Known AGNs in the Rosat-BSC (Cat. IX/10)
bsc_u.dat 110 3220 Unclassified sources (AGN candidates) in the BSC
fsc_k.dat 134 1008 Known AGNs in the Rosat-FSC (Cat. IX/29)
fsc_u.dat 134 9693 Unclassified sources (AGN candidates) in the FSC
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See also:
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
IX/10 : ROSAT All-Sky Bright Source Catalogue (1RXS) (Voges+ 1999)
IX/29 : ROSAT All-Sky Survey Faint Source Catalog (Voges+ 2000)
Byte-by-byte Description of file: bsc*.dat fsc*.dat
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Bytes Format Units Label Explanations
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1- 10 F10.6 deg RAdeg Right ascension (J2000) in 2MASS
12- 21 F10.6 deg DEdeg Declination (J2000) in 2MASS
23- 28 F6.3 mag Jmag 2MASS J selected default magnitude
30- 35 F6.3 mag Hmag 2MASS H selected default magnitude
37- 42 F6.3 mag Ksmag 2MASS Ks selected default magnitude
44- 52 F9.5 ct/s CRate Source count rate (1)
54- 62 F9.5 ct/s e_CRate ?=0 Error on CRate (1)
64- 74 E11.4 ct/s/arcmin2 bgCt ?=0 Background count rate (1)
76- 80 I5 s texp Exposure time
81- 82 A2 --- --- [.0]
84- 88 F5.2 --- HR1 [-1/1]? Hardness ratio 1 (2)
90- 94 F5.2 --- e_HR1 ? Error on HR1 (3)
96-100 F5.2 --- HR2 [-1/1]? Hardness ratio 2 (2)
102-106 F5.2 --- e_HR2 ? Error on HR2 (3)
108-110 I3 arcsec Extent Source extent, by which the source image
exceeds the point spread function
112-120 F9.2 "YYMMDD" Obs.beg ? Start time of observation (FSC only)
122-130 F9.2 "YYMMDD" Obs.end ? End time of observation (FSC only)
133-134 I2 --- Rel ? Reliability of source detection
(FSC data only)
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Note (1): Countrates are vignetting corrected
Note (2): The hardness ratios are defined by:
HR1=(B-A)/(B+A), where
A = count rate in PHA range 11-41 (∼0.1-0.4keV)
B = count rate in PHA range 52-201 (∼0.5-2.0keV)
HR2=(D-C)/(D+C), where
C = count rate in PHA range 52-90 (∼0.5-0.9keV)
D = count rate in PHA range 91-201 (∼0.9-2.0keV)
(PHA = Pulse Height Amplitude)
Note (3): The true mean error is probably bigger, and values larger than
9.99 are set to 9.99
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Acknowledgements:
S. Kouzuma, skouzuma(at)lets.chukyo-u.ac.jp
(End) Patricia Vannier [CDS] 19-Apr-2012