J/MNRAS/484/1021 Infrared-faint radio sources redshifts (Orenstein+, 2019)
The redshift distribution of infrared-faint radio sources.
Orenstein B.J., Collier J.D., Norris R.P.
<Mon. Not. R. Astron. Soc., 484, 1021-1030 (2019)>
=2019MNRAS.484.1021O 2019MNRAS.484.1021O (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies ; Redshifts ; Radio continuum ; Infrared sources
Keywords: galaxies: distances and redshifts - radio continuum: galaxies
Abstract:
Infrared-faint radio sources (IFRSs) are an important class of
high-redshift active galaxy, and potentially important as a means of
discovering more high-redshift radio sources, but only 25 IFRSs had
redshifts prior to this paper. Here we increase the number of IFRSs
with known spectroscopic redshifts, by a factor of about 5, to 131,
with redshifts up to z=4.387, and a median redshift of z=2.68. The
IFRS redshift distribution overlaps with the high-z radio galaxy
(HzRG) redshift distribution but is significantly narrower, suggesting
that the IFRSs are a subset of the larger class of HzRGs. We also
confirm and measure the proposed correlation between redshift and
3.6µm flux density, making it possible to use this correlation to
find even higher redshift radio sources. Many more high-redshift
sources are probably present in existing radio survey catalogues.
Description:
Our data were selected following a procedure similar to Collier et al.
(2014MNRAS.439..545C 2014MNRAS.439..545C, Cat. J/MNRAS/439/545), using deeper photometry
from WISE and more extensive spectroscopy from SDSS.
Our IFRS sample was taken from Version 2.0 of the Unified Radio
Catalogue (URC; Kimball & Ivezic 2008AJ....136..684K 2008AJ....136..684K; Kimball & Ivezic
2014IAUS..304..238K 2014IAUS..304..238K). This catalogue contains approximately three
million radio sources, and combines the 20cm flux density measurements
from the Faint Images of the Radio Sky at Twenty Centimeters (FIRST;
Becker, White & Helfand 1995ApJ...450..559B 1995ApJ...450..559B, Cat. VIII/92) survey, and
the NRAO-VLA Sky Survey (NVSS; Condon et al. 1998AJ....115.1693C 1998AJ....115.1693C, Cat.
VIII/65). We obtained infrared data from the AllWISE data release
(Cutri et al. 2014yCat.2328....0C 2014yCat.2328....0C, Cat. II/328), which improves upon
the sensitivity, photometric, and astrometric accuracy of the WISE
All-Sky data release. We converted 3.4µm measurements from
magnitudes to Jansky (Jy) with a flat colour correction factor, using
the conversion determined for IFRSs by Collier et al.
(2014MNRAS.439..545C 2014MNRAS.439..545C, Cat. J/MNRAS/439/545):
S3.4µm=306.682x10(-M3.4µm_/2.5)^Jy
We used spectroscopic redshifts from SDSS DR12 (Alam et al.
2015ApJS..219...12A 2015ApJS..219...12A, Cat. V/147). DR12 contains measurements from 2008
to 2014, taken by the third generation of SDSS.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table4.dat 55 2519 The large sample of radio sources
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See also:
VIII/92 : The FIRST Survey Catalog, Version 2014Dec17 (Helfand+ 2015)
VIII/65 : 1.4GHz NRAO VLA Sky Survey (NVSS) (Condon+ 1998)
II/328 : AllWISE Data Release (Cutri+ 2013)
V/147 : The SDSS Photometric Catalogue, Release 12 (Alam+, 2015)
Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- ID [1/2519] Unique object ID from 1-2519
6- 14 F9.5 deg RAdeg Right ascension (J2000) (1)
16- 24 F9.5 deg DEdeg Declination (J2000) (1)
26- 32 F7.1 mJy S20cm NVSS 20cm radio flux density (Condon et al.
1998AJ....115.1693C 1998AJ....115.1693C, Cat. VIII/65)
34- 39 F6.1 uJy S3.4um AllWISE 3.4um infrared flux density
(Cutri et al. 2014yCat.2328....0C 2014yCat.2328....0C,
Cat. II/328)
41- 47 F7.5 --- z SDSS DR12 spectroscopic redshift (Alam et al.
2015ApJS..219...12A 2015ApJS..219...12A, Cat. V/147)
49- 55 F7.5 --- e_z Error on z
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Note (1): The positions are taken from FIRST (Becker et al. 1995ApJ...450..559B 1995ApJ...450..559B,
Cat. VIII/92)
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History:
From electronic version of the journal
(End) Ana Fiallos [CDS] 16-Aug-2022