J/MNRAS/497/5383 GMRT 610-MHz survey of ELAIS N1 (Ishwara-Chandra+, 2020)
A wide-area GMRT 610-MHz survey of ELAIS N1 field.
Ishwara-Chandra C.H., Taylor A.R., Green D.A., Stil J.M., Vaccari M.,
Ocran E.F.
<Mon. Not. R. Astron. Soc., 497, 5383-5394 (2020)>
=2020MNRAS.497.5383I 2020MNRAS.497.5383I (SIMBAD/NED BibCode)
ADC_Keywords: Active gal. nuclei ; Radio sources ; Positional data
Keywords: surveys - catalogues - galaxies: active - radio continuum: galaxies
Abstract:
In this paper, we present a wide-area 610-MHz survey of the ELAIS N1
field with the GMRT, covering an area of 12.8deg2 at a resolution of
6arcsec and with an rms noise of ∼40µJy/beam. This is equivalent to
∼20µJy/beam rms noise at 1.4GHz for a spectral index of -0.75. The
primary goal of the survey was to study the polarized sky at sub-mJy
flux densities at <GHz frequencies, along with a range of other
science goals such as investigations into the nature of the
low-frequency µJy source populations and alignments of radio jets.
A total of 6400 sources were found in this region, the vast majority
of them compact. The sample jointly detected by GMRT at 610MHz and by
VLA FIRST at 1.4GHz has a median spectral index of -0.85±0.05 and a
median 610-MHz flux density of 4.5mJy. This region has a wealth of
ancillary data, which is useful to characterize the detected sources.
The multiwavelength crossmatching resulted optical/IR counterparts to
∼90 per cent of the radio sources, with a significant fraction having
at least photometric redshift. Due to the improved sensitivity of this
survey over preceding ones, we have discovered six giant radio sources
(GRSs), with three of them at z∼1 or higher. This implies that the
population of GRS may be more abundant and common than known to date
and if true, this has implications for the luminosity function and the
evolution of radio sources. We have also identified several
candidate-extended relic sources.
Description:
The ELAIS N1 field was originally chosen for deep extragalactic
observations with the Infrared Space Observatory (ISO) due to its low
infrared background (Rowan-Robinson et al. 2004MNRAS.351.1290R 2004MNRAS.351.1290R, Cat.
J/MNRAS/351/1290; Vaccari et al. 2005MNRAS.358..397V 2005MNRAS.358..397V, Cat.
J/MNRAS/358/397). Since then, it has gone on to become one of the best
studied 1-10deg2 extragalactic fields. The ELAIS N1 region, covering
∼10deg2, was observed at 610MHz using the Giant Metrewave Radio
Telescope (GMRT). The GMRT consists of 30 antennas of 45m diameter,
spread up to ∼25km baseline situated in western India (Swarup et al.
1991CSci...60...95S 1991CSci...60...95S). A total of 51 pointings were employed to cover
this area. The observations for most of the pointings were carried out
in 2011 and 2012 and a few remaining pointings were observed in
December 2017.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tables1.dat 108 6400 GMRT ELAIS N1 wide 610-MHz source catalogue
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Byte-by-byte Description of file: tables1.dat
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Bytes Format Units Label Explanations
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1- 14 A14 --- Name Source name (JHHMMSS-DDMMSS)
16- 24 F9.5 deg RAdeg Right ascension (J2000)
26- 29 F4.2 arcsec e_RAdeg Error on RAdeg
31- 38 F8.5 deg DEdeg Declination (J2000)
40- 43 F4.2 arcsec e_DEdeg Error on DEdeg
45- 51 F7.2 mJy SI Integrated Stokes I flux density
53- 57 F5.2 mJy e_SI Error on SI
59- 64 F6.2 mJy Sp Peak Stokes I intensity
66- 70 F5.2 mJy/beam e_Sp Error on Sp
72- 76 F5.3 mJy/beam RMS RMS at the source position returned by
PyBDSF
78- 81 F4.1 arcsec thetamaj Dimension of the fitted major axis of 2D
Gaussian
83- 85 F3.1 arcsec e_thetamaj Error on thetamaj
87- 90 F4.1 arcsec thetamin Dimension of the fitted minor axis of 2D
Gaussian
92- 94 F3.1 arcsec e_thetamin Error on thetamin
96- 100 F5.1 deg PA Position angle of the source major axis
with respect to north
102- 106 F5.1 deg e_PA Error on PA
108 A1 --- Code Source classification code, as in
(Mohan & Rafferty 2015ascl.soft02007M)
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History:
From electronic version of the journal
(End) Ana Fiallos [CDS] 27-Jul-2023