J/ApJ/679/140 IR measurement of quasar obscuration (Treister+, 2008)
Measuring the fraction of obscured quasars by the infrared luminosity of
unobscured quasars.
Treister E., Krolik J.H., Dullemond C.
<Astrophys. J., 679, 140-148 (2008)>
=2008ApJ...679..140T 2008ApJ...679..140T
ADC_Keywords: QSOs ; Photometry, SDSS ; Photometry, infrared ; Ultraviolet
Keywords: galaxies: active - infrared: galaxies - quasars: general
Abstract:
Recent work has suggested that the fraction of obscured AGNs declines
with increasing luminosity, but it has been difficult to quantify this
trend. Here we attempt to measure this fraction as a function of
luminosity by studying the ratio of mid-infrared to intrinsic nuclear
bolometric luminosity in unobscured AGNs. Because the mid-infrared is
created by dust reprocessing of shorter wavelength nuclear light, this
ratio is a diagnostic of fobsc, the fraction of solid
angle around the nucleus covered by obscuring matter. In order to
eliminate possible redshift dependences while also achieving a large
dynamic range in luminosity, we have collected archival 24um MIPS
photometry from objects with z∼1 in the Sloan Digital Sky Survey DR5,
the Great Observatories Origins Deep Survey, and the Cosmic Evolution
Survey. To measure the bolometric luminosity for each object, we used
archival optical data supplemented by GALEX data.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 115 206 Observed properties of sources in the SDSS sample
table3.dat 115 14 Observed properties of sources in the COSMOS sample
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See also:
II/294 : The SDSS Photometric Catalog, Release 7 (Adelman-McCarthy+, 2009)
II/284 : COSMOS Multi-Wavelength Photometry Catalog (Capak+, 2007)
II/261 : GOODS initial results (Giavalisco+, 2004)
J/ApJ/640/603 : Catalog of AGNs in the GOODS fields (Treister+, 2006)
J/ApJS/172/383 : AGN candidates in the COSMOS field (Trump+, 2007)
J/AJ/133/1780 : GALEX/SDSS quasar catalog (Trammell+, 2007)
Byte-by-byte Description of file: table1.dat table3.dat
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Bytes Format Units Label Explanations
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1- 6 A6 --- Sample [SDSS/COSMOS] Name of sample
8- 26 A19 --- Name Name (SDSS for table1 or COSMOS for table3
JHHMMSS.ss+DDMMSS.s)
28- 32 F5.3 --- z Redshift (spectroscopic)
34- 39 F6.3 mag umag SDSS u band AB magnitude
41- 46 F6.3 mag gmag SDSS g band AB magnitude
48- 53 F6.3 mag rmag SDSS r band AB magnitude
55- 60 F6.3 mag imag SDSS i band AB magnitude
62- 67 F6.3 mag zmag SDSS z band AB magnitude
69 A1 --- l_F24um Upper limit flag on F24um
70- 74 F5.3 fW/m2 F24um Spitzer/MIPS 24 micron band flux (1)
76- 80 F5.3 fW/m2 FNUV GALEX NUV band flux (1)
82- 86 F5.3 fW/m2 E_FNUV ? Upper 1σ bound on FNUV (1)
88- 92 F5.3 fW/m2 e_FNUV ? Lower 1σ bound on FNUV (1)
94- 98 F5.3 fW/m2 FFUV GALEX FUV band flux (1)
100-104 F5.3 fW/m2 E_FFUV ? Upper 1σ bound on FFUV (1)
106-110 F5.3 fW/m2 e_FFUV ? Lower 1σ bound on FFUV (1)
112-115 F4.1 [10-7W] Lbol Log of the bolometric luminosity
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Note (1): fluxes are expressed in 10-12erg/cm2/s = 10-15W/m2
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 22-Sep-2010