J/MNRAS/438/1149 WISE data for radio-loud AGN complete samples (Gurkan+, 2014)
The Wide-field Infrared Survey Explorer properties of complete samples of
radio-loud active galactic nucleus.
Gurkan G., Hardcastle M.J., Jarvis M.J.
<Mon. Not. R. Astron. Soc., 438, 1149-1161 (2014)>
=2014MNRAS.438.1149G 2014MNRAS.438.1149G
ADC_Keywords: Active gal. nuclei ; Photometry, infrared
Keywords: galaxies: active - galaxies: nuclei - infrared: galaxies
Abstract:
We present an analysis of four complete samples of radio-loud active
galactic nucleus (AGN; 3CRR, 2Jy, 6CE and 7CE) using near- and mid-IR
data taken by the Wide-field Infrared Survey Explorer (WISE). The
combined sample consists of 79 quasars and 273 radio galaxies, and
covers a redshift range 0.003<z<3.395. The dichotomy in the mid-IR
properties of low- and high-excitation radio galaxies (LERGs and
HERGs) is analysed for the first time using large complete samples.
Our results demonstrate that a division in the accretion modes of
LERGs and HERGs clearly stands out in the mid-IR-radio plane
(L22µm=5x1043erg/s). This means that WISE data can be
effectively used to diagnose accretion modes in radio-loud AGN. The
mid-IR properties of all objects were analysed to test the unification
between quasars and radio galaxies, consistent with earlier work, and
we argue that smooth torus models best reproduce the observation.
Quasars are found to have higher mid-IR luminosities than radio
galaxies. We also studied all the sources in the near-IR to gain
insights into evolution of AGN host galaxies. A relation found between
the near-IR luminosity and redshift, well known in the near-IR, is
apparent in the two near-IR WISE bands, supporting the idea that radio
sources are hosted by massive elliptical galaxies that formed their
stars at high redshifts and evolved passively thereafter. Evaluation
of the positions of the sample objects in WISE colour-colour diagrams
shows that widely used WISE colour cuts are not completely reliable in
selecting AGN.
Description:
The 3CRR, 2Jy, 6CE and 7CE samples were chosen for our analysis.
We used the revised subsample of the 3CR catalogue of radio sources
(Bennett, 1962MNRAS.125...75B 1962MNRAS.125...75B), which have flux densities greater than
10.9Jy at 178MHz (Laing, Riley & Longair, 1983MNRAS.204..151L 1983MNRAS.204..151L, Cat.
J/MNRAS.204.151). There are 172 sources with 0.0029<z<2.012 including
37 LERGs, 82 NLRGs, 10 BLRGs and 43 quasars. 3C231 was excluded from
the analysis as its radio emission is due to a starburst.
Another complete radio sample chosen for our analysis is a subsample
of the 2Jy objects, which has homogeneous spectroscopic observations
(Wall & Peacock, 1985MNRAS.216..173W 1985MNRAS.216..173W, Cat. J/MNRAS/216/173; Tadhunter
et al. 1993MNRAS.263..999T 1993MNRAS.263..999T). The complete sample was generated
selecting radio objects with flux densities above 2Jy at 2.7GHz. Our
subsample consists of 48 steep-spectrum sources (objects dominated by
emission from the beamed relativistic jet and core components are
excluded so that we minimize the contamination from non-thermal
emission) with 0.05<z<0.7, which have mid-far-infrared imaging
and spectra taken by Spitzer as well as 98 per cent complete
Chandra/XMM X-ray imaging. This sample has 10 LERGs, 20 NLRGs, 13
BLRGs and 5 quasars.
The 6CE subsample is drawn from the 6C survey (Baldwin et al.,
1985MNRAS.217..717B 1985MNRAS.217..717B, Cat. VIII/18) and was designed to select objects
fainter than 3C objects, in order to investigate the cosmic evolution
of radio galaxies (Eales 1985MNRAS.217..149E 1985MNRAS.217..149E; Eales et al.
1997MNRAS.291..593E 1997MNRAS.291..593E). The flux density limit for the sample is
2≤S_151+≤3.93Jy. It has virtually complete spectroscopic redshift
measurements as well as IR imaging . The 6CE sample has 58 sources
including 19 LERGs, 28 HERGs and 9 quasars, whose redshift ranges
between 0.105 and 3.395.
The 7CE sample, drawn from the 7C survey (Visser et al.,
1995A&AS..110..419V 1995A&AS..110..419V, Cat. J/A+AS/110/419), is a complete sample having
flux densities greater than 0.5Jy at 151MHz (Willott et al.,
1998MNRAS.300..625W 1998MNRAS.300..625W, 2002MNRAS.335.1120W 2002MNRAS.335.1120W). This sample has 90
per cent spectroscopic redshift completeness and 49 radio galaxies
have near-IR imaging (Willott et al. 2003MNRAS.339..173W 2003MNRAS.339..173W). It
comprises 74 radio sources covering redshift from 0.086 to 2.982: 4
LERGs, 46 NLRGs, 2 BLRGs and 22 quasars.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
2jy.dat 322 48 WISE magnitudes of the 2Jy sample
3crr.dat 322 172 WISE magnitudes of the 3CRR sample
6ce.dat 322 56 WISE magnitudes of the 6CE sample
7ce.dat 322 74 WISE magnitudes of the 7CE sample
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See also:
VIII/18 : 6C Survey of radio sources I. (Baldwin+ 1985)
J/MNRAS/216/173 : Bright extragalactic radio sources at 2.7 GHz (Wall+, 1985)
J/A+AS/110/419 : 7C: survey of radio sources (Visser+, 1995)
Byte-by-byte Description of file: *.dat
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Bytes Format Units Label Explanations
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1- 14 A14 --- Name Source name
17- 22 F6.4 --- z Redshift
24- 43 F20.17 mag [3.4] 3.4um magnitude (Vega)
45- 65 F21.18 mag e_[3.4] rms uncertainty on [3.4]
67- 84 F18.15 mag [4.6] 4.6um magnitude (Vega)
86-103 F18.15 mag e_[4.6] ?=0 rms uncertainty on [4.6]
105-122 F18.15 mag [12] ?=0 12um magnitude (Vega)
124-140 F17.15 mag e_[12] ?=0 rms uncertainty on [12]
142-159 F18.16 mag [22] ?=0 22um magnitude (Vega)
160-171 E12.9 mag e_[22] ?=0 rms uncertainty on [22]
174-194 E21.16 Jy F3.4 [0.00002/0.191]?=0 WISE/W1 flux at 3.4um
196-216 E21.16 Jy e_F3.4 ?=0 rms uncertainty on F3.4
218-238 E21.16 Jy F4.6 [0.00002/0.186]?=0 WISE/W2 flux at 4.6um
240-260 E21.16 Jy e_F4.6 ?=0 rms uncertainty on F4.6
262-277 E16.9 Jy F12 [0.0001/0.690]?=0 WISE/W3 flux at 12um
279-294 E16.11 Jy e_F12 ?=0 rms uncertainty on F12
296-307 E12.9 Jy F22 [0.0009/2.873]?=0 WISE/W4 flux at 22um
311-322 E12.9 Jy e_F22 ?=0 rms uncertainty on F22
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 28-Nov-2014