J/MNRAS/434/956 AT20G high-angular-resolution catalogue (Chhetri+, 2013)
The AT20G high-angular-resolution catalogue.
Chhetri R., Ekers R.D., Jones P.A., Ricci R.
<Mon. Not. R. Astron. Soc., 434, 956-965 (2013)>
=2013MNRAS.434..956C 2013MNRAS.434..956C
ADC_Keywords: Surveys ; Radio sources ; QSOs ; Interferometry
Keywords: techniques: interferometric - catalogues - surveys -
galaxies: active - quasars: general - radio continuum: general
Abstract:
We present the high-angular-resolution catalogue for the Australia
Telescope 20GHz (AT20G, Cat. J/MNRAS/402/2403) survey, using the
high-angular-resolution 6-km antenna data at the baselines of ∼4500m
of the Australia Telescope Compact Array. We have used the data to
produce the visibility catalogue that separates the compact active
galactic nuclei (AGNs) from the extended radio sources at the
0.15arcsec angular scale, corresponding to the linear size scale of
1kpc at redshifts higher than 0.7. We find the radio population at
20GHz to be dominated by compact AGNs constituting 77% of the total
sources in the AT20G. We introduce the visibility-spectra diagnostic
plot, produced using the AT20G cross-matches with lower frequency
radio surveys at 1GHz [the NRAO VLA Sky Survey (NVSS, Cat. VIII/65)
and the Sydney University Molonglo Sky Survey (SUMSS, Cat. VIII/81)],
that separates the 20GHz population into distinct sub-populations of
the compact AGNs, the compact steep-spectrum (CSS) sources, the
extended AGN-powered sources and extended flat-spectrum sources. The
extended flat-spectrum sources include a local thermal emitting
population of high-latitude planetary nebulae and also gravitational
lens and binary black hole candidates among the AGNs. We find a smooth
transition in properties between the CSS sources and the AGN
populations. The visibility catalogue, together with the main AT20G
survey, provides an estimate of angular size scales for sources in the
AT20G and an estimate of the flux arising from central cores of
extended radio sources. The identification of the compact AGNs in the
AT20G survey provides high-quality calibrators for high-frequency
radio telescope arrays and very large baseline interferometry
observations.
Description:
For data processing we used the Multichannel Image Reconstruction,
Image Analysis and Display (MIRIAD; Sault, Teuben & Wright, 1995, ASP
Conf. Ser., Vol. 77, p. 433) software package. We used the AT20G
survey data after the initial data quality checks implemented in an
automated custom analysis pipeline as described by Murphy et al.
(2010MNRAS.402.2403M 2010MNRAS.402.2403M). We then calculated the visibilities on the
4500m baselines in a separate custom pipeline.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 126 5890 Visibility catalogue of the AT20G survey
table3.dat 49 898 6-km visibilities for sources for which more
than two 6-km visibilities are present
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See also:
J/MNRAS/402/2403 : Australia Telescope 20GHz Survey Catalog (Murphy+, 2010)
J/MNRAS/417/2651 : AT20G-optical catalogue (Mahony+, 2011)
J/ApJ/718/587 : The Fermi-AT20G catalog (Mahony+, 2010)
J/ApJ/732/45 : VLA fluxes for AT20G radio galaxies (Sajina+, 2011)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 14 A14 --- AT20G AT20G 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- 38 F4.1 arcsec DEs Declination (J2000)
40- 44 I5 mJy S20 [40/28350] 20GHz flux density
46- 49 I4 mJy S8.6 [5/6566]?=- 8.6GHz flux density
51- 54 I4 mJy S4.8 [3/9066]?=- 4.8GHz flux density
56- 61 I6 mJy S1.4 [2/113563]?=- NVSS 1.4GHz flux density
63- 68 I6 mJy S0.8 [8/342000]?=- SUMSS 0.8GHz flux density
70- 74 F5.2 --- SI1-5 [-2.1/2.3]?=- Spectral index between 1 and 4.8GHz
76- 80 F5.2 --- SI1-9 [-2.0/2.1]?=- Spectral index between 1 and 8.6GHz
82- 86 F5.2 --- SI1-20 [-2.1/1.6]?=- Spectral index between 1 and 20GHz
88- 92 F5.2 --- SI5-9 [-2.6/2.9]?=- Spectral index between 4.8
and 8.6GHz
94- 98 F5.2 --- SI5-20 [-2.3/1.9]?=- Spectral index between 4.8
and 20GHz
100-104 F5.2 --- SI9-20 [-3.0/2.5]?=- Spectral index between 8.6
and 20GHz
106-110 F5.2 --- Vis1 ?=- First 6-km visibility (G1)
112-116 F5.2 --- Vis2 ?=- Second 6-km visibility (G1)
118-121 F4.2 --- e_Vis ?=- Total uncertainty in the 6-km visibility
123-126 A4 --- Flag Flags (1)
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Note (1): Flag as follows:
n = there are no 6-km visibilities for this source
v = more than two 6-km visibilities are present. They are listed in Table 3.
e = the source is flagged as "extended" in the AT20G survey and corresponds
to angular size greater than ∼5arcsec
h = source is identified as an HII region
p = source is identified as a planetary nebula (Cat. V/127, Parker et al.
2006MNRAS.373...79P 2006MNRAS.373...79P; Miszalski et al. 2008MNRAS.384..525M 2008MNRAS.384..525M)
m = source is identified as part of Magellanic Clouds
l = source has no match in the lower frequency surveys (NVSS and SUMSS)
b = source is flagged as large and extended in the AT20G survey
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 14 A14 --- AT20G AT20g name (JHHMMSS+DDMMSS)
16- 19 F4.2 --- Vis1 First 6-km visibility (G1)
21- 24 F4.2 --- Vis2 ?=- Second 6-km visibility (G1)
26- 29 F4.2 --- Vis3 ?=- Third 6-km visibility (G1)
31- 34 F4.2 --- Vis4 ?=- Fourth 6-km visibility (G1)
36- 39 F4.2 --- Vis5 ?=- Fifth 6-km visibility (G1)
41- 44 F4.2 --- Vis6 ?=- Sixth 6-km visibility (G1)
46- 49 F4.2 -- e_Vis Uncertainty in all the 6-km visibilities
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Global notes:
Note (G1): 6-km visibilities after bias correction according to equation (2),
6-km visibility* = SQRT((AL)2-sigma2)/SQRT((AS)2-sigma2),
where 6-km visibility* is the corrected 6-km visibility, AL is the scalar
averaged amplitude of all 6-km antenna baselines (in mJy), AS is the scalar
averaged amplitude of all short baselines (in mJy) and sigma is the rms
noise per integration =36mJy.
The visibilities are presented in the ascending order.
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 01-Aug-2014