J/MNRAS/471/210 eMERGE Survey. I. VLA 5.5GHz sources (Guidetti+, 2017)
The eMERGE Survey.
I: Very Large Array 5.5 GHz observations of the GOODS-North Field.
Guidetti D., Bondi M., Prandoni I., Muxlow T.W.B., Beswick R., Wrigley N.,
Smail I., Mchardy I., Thomson A.P., Radcliffe J., Argo M.K.
<Mon. Not. R. Astron. Soc., 471, 210-226 (2017)>
=2017MNRAS.471..210G 2017MNRAS.471..210G (SIMBAD/NED BibCode)
ADC_Keywords: Active gal. nuclei ; Radio sources ; Redshifts ; Morphology
Keywords: galaxies: active - galaxies: evolution - galaxies: starburst
cosmology: observations - radio continuum: galaxies
Abstract:
We present new observations of the GOODS-N field obtained at 5.5GHz
with the Karl G. Jansky Very Large Array. The central region of the
field was imaged to a median rms of 3µJy/beam with a resolution of
0.5 arcsec. From a 14-arcmin diameter region, we extracted a sample of
94 radio sources with signal-to-noise ratio greater than 5. Near-IR
identifications are available for about ∼88 per cent of the radio
sources. We used different multiband diagnostics to separate active
galactic nuclei (AGNs), both radiatively efficient and inefficient,
from star-forming galaxies. From our analysis, we find that about 80
per cent of our radio-selected sample is AGN dominated, with the
fraction rising to 92 per cent when considering only the radio sources
with redshift >1.5. This large fraction of AGN-dominated radio sources
at very low flux densities (the median flux density at 5.5GHz is
42µJy), where star-forming galaxies are expected to dominate, is
somewhat surprising and at odds with other results. Our interpretation
is that both the frequency and angular resolution of our radio
observations strongly select against radio sources whose brightness
distribution is diffuse on a scale of several kpc. Indeed, we find
that the median angular sizes of the AGN-dominated sources is around
0.2-0.3arcsec against 0.8 arcsec for star-forming galaxies. This
highlights the key role that high frequency radio observations can
play in pinpointing AGN-driven radio emission at µJy levels. This
work is part of the eMERGE legacy project.
Description:
We obtained new VLA observations of the GOODS-N field at a central
frequency of 5.5GHz with a 2GHz bandwidth in A- and B-configurations.
The VLA A-configuration observations were taken over four nights in
2012 October (2012 October 6-8 and 20, project code 12B-181), for a
total observing time of 14h. The B-configuration data were taken in
one night (2013 September 27, project code 13B-152) for a total time
of 2.5h.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 95 94 The catalogue of source detected above
5 sigma at 5.5GHz
table2.dat 34 8 Polarized sources
table4.dat 44 77 Multiwavelength classification for the 5.5GHz
sources with NIR identification
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See also:
J/ApJ/689/687 : GOODS-N spectroscopic survey (Barger+, 2008)
J/ApJS/235/34 : Deep JVLA imaging of GOODS-N at 20cm (Owen, 2018)
J/A+A/619/A48 : GOODS-N AGN VLBI detect. & radio properties (Radcliffe+, 2018)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 14 A14 --- Name Source name (JHHMMSS+DDMMSS)
16- 17 I2 h RAh Right ascension (J2000)
19- 20 I2 min RAm Right ascension (J2000)
22- 26 F5.2 s RAs Right ascension (J2000)
28 A1 --- DE- Declination sign (J2000)
29- 30 I2 deg DEd Declination (J2000)
32- 33 I2 arcmin DEm Declination (J2000)
35- 39 F5.2 arcsec DEs Declination (J2000)
41- 44 F4.2 arcsec e_RAs Error on RA (arcsec)
46- 49 F4.2 arcsec e_DEs Error on DE (arcsec)
51- 55 F5.1 --- S/N Signal-to-noise ratio
57- 62 F6.1 uJy/beam Fpeak Peak brightness at 5GHz
64- 67 F4.1 uJy/beam e_Fpeak Error on peak brightness at 5GHz
69- 74 F6.1 uJy Ftot Total flux density at 5GHz
76- 79 F4.1 uJy e_Ftot Error on total flux density at 5GHz
81- 85 F5.2 arcsec Amaj ?=-9 Deconvolved sizes: major axis
87- 91 F5.2 arcsec Bmin ?=-9 Deconvolved sizes: minor axis
93- 95 I3 deg PA ?=-99 Deconvolved sizes: position angle
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 14 A14 --- Name Source name (JHHMMSS+DDMMSS)
16- 19 F4.1 uJy Ppeak Peak of polarized emission at 5GHz
21- 24 F4.1 --- SNRP SNR of the polarized emission
26- 29 F4.1 uJy Ptot Total polarized emission at 5GHz
31- 34 F4.1 % Pol Average fractional polarization at 5GHz
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 14 A14 --- Name Source name (JHHMMSS+DDMMSS)
16- 20 F5.3 --- z z Spectroscopic (s) or photometric (p) redshift
22 A1 --- n_z [s/p] Spectroscopic (s) or photometric (p)
redshift
24- 31 A8 --- ClassIR Classification based on the four IR diagnotics
33 A1 --- X-ray [Y/N] X-ray AGN (Y) or not (N)
35 A1 --- Radio-exc [Y/N] Radio-excess AGN (Y) or not (N)
37 A1 --- VLBI [Y/N] VLBI detected sources (Y) or not (N)
39- 44 A6 --- Class Final classification combining all the
multiwavelength diagnostics
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 15-May-2020