J/ApJ/645/856 Beamed radio-intermediate quasars (Wang+, 2006)
Evidence for a population of beamed radio-intermediate quasars.
Wang T.-G., Zhou H.-Y., Wang J.-X., Lu Y.-J., Lu Y.
<Astrophys. J., 645, 856-860 (2006)>
=2006ApJ...645..856W 2006ApJ...645..856W
ADC_Keywords: QSOs ; Radio sources
Keywords: galaxies: jets - quasars: general - radio continuum: galaxies
Abstract:
Whether radio-intermediate quasars possess relativistic jets as
radio-loud quasars do is an important issue in the understanding of
the origin of radio emission in quasars. In this paper, using the
two-epoch radio data obtained during the Faint Images of the Radio Sky
at Twenty cm (FIRST) and NRAO VLA Sky Survey (NVSS), we identified 89
radio-variable sources in the Sloan Digital Sky Survey (SDSS). Among
them, more than half are radio-intermediate quasars
(RL=f20cm/f2500Å<250). For all objects with available
multiple-band radio observations, the radio spectra are either flat or
inverted. The brightness temperature inferred from the variability is
larger than the synchrotron self-Compton limit for a stationary source
in 87 objects, indicating relativistic beaming. Considering the sample
selection and the viewing angle effect, we conclude that relativistic
jets probably exist in a substantial fraction of radio-intermediate
quasars.
Description:
The sample was selected by cross-correlating the Third Data Release
(DR3) of the SDSS Quasar Catalog (Schneider et al., 2005, Cat.
VII/243) with the FIRST catalog (ver. 03Apr11; Becker et al., 1995,
Cat. VIII/71) and NVSS catalog (Condon et al., 1998, Cat.
VIII/65).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 107 86 Basic data of Radio Variable Quasars
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See also:
VIII/65 : 1.4GHz NRAO VLA Sky Survey (NVSS) (Condon+ 1998)
VIII/71 : The FIRST Survey Catalog, Version 03Apr11 (Becker+ 2003)
VII/243 : SDSS quasar catalog. III. (Schneider+, 2005)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 2 I2 h RAh Hour of Right Ascension (J2000)
4- 5 I2 min RAm Minute of Right Ascension (J2000)
7- 11 F5.2 s RAs Second of Right Ascension (J2000)
13 A1 --- DE- Sign of the Declination (J2000)
14- 15 I2 deg DEd Degree of Declination (J2000)
17- 18 I2 arcmin DEm Arcminute of Declination (J2000)
20- 23 F4.1 arcsec DEs Arcsecond of Declination (J2000)
25- 30 F6.4 --- z Redshift
32- 37 F6.3 mag g'mag SDSS g' band magnitude
39- 43 F5.3 mag e_g'mag Uncertainty in g'mag
45- 50 F6.2 mJy SFIRST FIRST 20cm flux density
52- 55 F4.2 mJy e_SFIRST Uncertainty in SFIRST
57- 66 A10 --- FIRST.Date Date of FIRST observation, in YYYY/MM/DD (1)
68- 73 F6.2 mJy SNVSS NRAO VLA Sky Survey flux density
75- 79 F5.2 mJy e_SNVSS Uncertainty in SNVSS
81- 90 A10 --- NVSS.Date Date of NVSS observation, in YYYY/MM/DD (1)
92- 95 F4.2 [-] logRL Log of the radio loudness (see text)
97-101 F5.2 [K] logTb Log of the brightness temperature
103-107 F5.2 --- Doppler Doppler factor (see text)
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Note (1): Day could not be present.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 05-Oct-2007