J/MNRAS/357/1267 bjur photometry and redshifts of QSOs (Cirasuolo+, 2005)
Faint radio-loud quasars: clues to their evolution.
Cirasuolo M., Magliocchetti M., Celotti A.
<Mon. Not. R. Astron. Soc., 357, 1267-1280 (2005)>
=2005MNRAS.357.1267C 2005MNRAS.357.1267C
ADC_Keywords: QSOs ; Radio sources ; Photometry ; Redshifts
Keywords: galaxies: active - quasars: general - cosmology: observations -
radio continuum: galaxies
Abstract:
The quasar sample selected by cross-correlating the Faint Images of
the Radio Sky at Twenty cm (FIRST, VIII/71) survey and the 2-degree
Field Quasar Redshift Survey (2QZ, VII/223) allows us to explore,
for the first time, the faint end of the radio and optical luminosity
functions up to z≃2.2. We find indications (∼3σ) of a negative
evolution for these faint sources at z≳1.8, both in radio and optical
bands. This corresponds to a decrement in the space density of faint
quasars of approximately a factor 2 at z=2.2 and confirms the presence
of a differential evolution for the population of radio-active
quasars. The faint end of both luminosity functions flattens and the
comparison with the (optical) number density of the whole quasar
population supports a dependence of the fraction of radio-detected
quasars on the optical luminosity. A progressive decrease in the
fraction of quasars in the whole radio source population can be
consistently accounted for within the receding torus scenario. The
population of low-luminosity quasars, which the FIRST-2dF detects,
appears to depart from the classical scheme for radio-loud quasars.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 85 238 Optical and radio properties of the FIRST-2QZ
quasar sample (not included in Cirasuolo et al.
2003, Cat. J/MNRAS/341/993)
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See also:
J/MNRAS/341/993 : ujbr photometry and redshifts of QSOs (Cirasuolo+, 2003)
VII/223 : The 2dF QSO Redshift Survey. V. The 10k cat. (Croom+ 2001)
VII/241 : The 2dF QSO Redshift Survey (Croom+ 2004)
VIII/71 : The FIRST Survey Catalog, Version 03Apr11 (Becker+ 2003)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 16 A16 --- 2dF 2dF name (JHHMMSS.s+DDMMSS)
18- 19 I2 h RAh Right ascension (J2000)
21- 22 I2 min RAm Right ascension (J2000)
24- 28 F5.2 s RAs Right ascension (J2000)
30 A1 --- DE- Declination sign (J2000)
31- 32 I2 deg DEd Declination (J2000)
34- 35 I2 arcmin DEm Declination (J2000)
37- 40 F4.1 arcsec DEs Declination (J2000)
42- 47 F6.3 mag bjmag bj magnitude
49- 54 F6.3 mag u-bj u-bj colour index
56- 61 F6.3 mag bj-r bj-r colour index
63- 70 F8.3 mJy S1.4GHz Radio-flux density at 1.4GHz
72- 76 F5.3 ---- z Redshift
78 A1 ---- Morph [dtm] Radio morphological appearance (1)
80- 85 F6.3 ---- alphaR ? Radio spectral index
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Note (1): Notes as follows:
d = double source (i.e. presenting the two characteristic lobes)
t = core + lobes structure
m = cases in which the source is decomposed in more than three
substructures; this information has been obtained by visual
inspection of the images of each radio object from the FIRST atlas.
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 09-Feb-2006