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J/AJ/121/2843 QSOs in 2MASS second incremental data release (Barkhouse+, 2001)
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Quasars in the 2MASS second incremental data release.
Barkhouse W.A., Hall P.B.
<Astron. J. 121, 2843 (2001)>
=2001AJ....121.2843B
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ADC_Keywords: QSOs ; Radio sources ; Photometry, infrared
Keywords: catalogs - galaxies: active - infrared: general - quasars: general
Abstract:
Using the 2MASS Second Incremental Data Release (Cat. <B/2mass>), we
have searched for near-infrared counterparts to 13214 quasars from the
Veron-Cetty & Veron (Cat. <VII/215>) catalog. We have detected
counterparts within 4" for 2277 of the approximately 6320 quasars
within the area covered by the 2MASS Second Incremental Data Release.
Only 1.6% of these are expected to be chance coincidences. Though this
sample is heterogeneous, we find that known radio-loud quasars are
more likely to have large near-infrared-to-optical luminosity ratios
than radio-quiet quasars are, at a statistically significant level.
This is consistent with dust-reddened quasars being more common in
radio-selected samples than in optically selected samples, due to
stronger selection effects against dust-reddened quasars in the
latter. We also find a statistically significant dearth of optically
luminous quasars with large near-infrared-to-optical luminosity
ratios. This can be explained in a dust obscuration model but not in a
model where synchrotron emission extends from the radio into the
near-infrared and creates such large ratios. We also find that
selection of quasar candidates from the B-J/J-K color-color diagram,
modeled on the V-J/J-K selection method of Warren, Hewett, & Foltz, is
likely to be more sensitive to dust-obscured quasars than selection
using only infrared-infrared colors.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 143 2279 VV00 Quasars Detected in 2MASS
table2.dat 58 3999 VV00 Quasars With Only Upper Limits in 2MASS
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See also:
VII/215 : Quasars and Active Galactic Nuclei (9th Ed.) (Veron+ 2000)
VII/224 : Quasars and Active Galactic Nuclei (10th Ed.) (Veron+ 2001)
B/2mass : The 2MASS database (IPAC/UMass, 2000)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1 A1 --- f_2MASS [*] Indicates an object having two 2MASS
counterparts within 4''.
2- 15 A14 --- 2MASS The 2MASS identification
17- 33 A17 --- VV00 Name entries of Veron-Cetty & Veron 2000 (1)
35- 44 F10.6 deg RAdeg Right Ascension in degrees (J2000)
46- 55 F10.6 deg DEdeg Declination in degrees (J2000)
57- 61 F5.2 [Jy] LNIR Log of the NIR luminosity
63- 67 F5.2 [Jy] Lopt Log of the Optical luminosity
69- 73 F5.2 mag bmag The b_m_ band magnitude
75- 79 F5.2 mag rmag The r_m_ band magnitude
81- 86 F6.3 mag Jmag The J band magnitude
88- 92 F5.3 mag e_Jmag Uncertainty in Jmag
94- 99 F6.3 mag Hmag The H band magnitude
101-105 F5.3 mag e_Hmag Uncertainty in Hmag
107-112 F6.3 mag Kmag The K band magnitude
114-118 F5.3 mag e_Kmag Uncertainty in Kmag
120-125 F6.2 mag BMag Absolute B band magnitude (2)
127-130 F4.2 arcsec Dis Distance to the associated optical source
132-137 F6.2 Jy Radio ?=-99.00 Flux density at 6 cm (3)
139-143 F5.3 --- z Redshift (2)
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Note (1): Objects which have blank Name entries in Veron-Cetty & Veron
(2000, Cat. <VII/215>) are identified here by the prefix VV followed
by their coordinates in Veron-Cetty & Veron (2000, Cat. <VII/215>).
Note (2): Data from Veron-Cetty & Veron (2000, Cat. <VII/215>).
Note (3): Data from Veron-Cetty & Veron (2000, Cat. <VII/215>).
Unavailable data entries are given as -99.00.
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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- 17 A17 --- VV00 Name entry of Veron-Cetty & Veron (2000) (1)
19- 28 F10.6 deg RAdeg Right Ascension in degrees (J2000)
30- 39 F10.6 deg DEdeg Declination in degrees (J2000)
41- 45 F5.2 [Jy] Lopt Log of the optical luminosity
47- 52 F6.2 Jy Radio ?=-99.00 Flux density measured at 6 cm (2)
54- 58 F5.3 --- z Redshift
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Note (1): Objects which have blank Name entries in Veron-Cetty & Veron
(2000, Cat. <VII/215>) are identified here by the prefix VV followed
by their coordinates in Veron-Cetty & Veron (2000, Cat. <VII/215>).
Note (2): Unavailable data entries are given as -99.00.
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History:
From electronic version of the journal
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(End) Greg Schwarz [AAS], Patricia Bauer [CDS] 30-Aug-2001