J/MNRAS/443/2590 The VLA-COSMOS Survey. V. 324MHz (Smolcic+, 2014)
The VLA-COSMOS Survey. V. 324 MHz continuum observations.
Smolcic V., Ciliegi P., Jelic V., Bondi M., Schinnerer E., Carilli C.L.,
Riechers D.A., Salvato M., Brkovic A., Capak P., Ilbert O., Karim A.,
Mccracken H., Scoville N.Z.
<Mon. Not. R. Astron. Soc., 443, 2590-2598 (2014)>
=2014MNRAS.443.2590S 2014MNRAS.443.2590S
ADC_Keywords: Radio continuum ; Galaxies, radio
Keywords: radiation mechanisms: general - surveys - radio continuum: galaxies
Abstract:
We present 90cm Very Large Array imaging of the COSMOS field,
comprising a circular area of 3.14 square degrees at
8.0"x6.0" angular resolution with an average rms of 0.5mJy/beam. The
extracted catalogue contains 182 sources (down to 5.5σ), 30 of
which are multicomponent sources. Using Monte Carlo artificial source
simulations, we derive the completeness of the catalogue, and we show
that our 90cm source counts agree very well with those from previous
studies. Using X-ray, NUV-NIR and radio COSMOS data to investigate the
population mix of our 90cm radio sample, we find that our sample is
dominated by active galactic nuclei. The average 90-20cm spectral
index (Sν∝να, where Sν is the flux
density at frequency ν and α the spectral index) of our 90cm
selected sources is -0.70, with an interquartile range from -0.90 to
-0.53. Only a few ultra-steep-spectrum sources are present in our
sample, consistent with results in the literature for similar fields.
Our data do not show clear steepening of the spectral index with
redshift. Nevertheless, our sample suggests that sources with spectral
indices steeper than -1 all lie at z≳1, in agreement with the idea
that ultra-steep-spectrum radio sources may trace
intermediate-redshift galaxies (z≳1).
Description:
Observations were performed in 2008 November with the VLA in its A
configuration. The receivers were tuned to 324MHz (90cm, P band). A
single pointing towards the COSMOS field (centred at 10:00:28.6,
+02:12:21) was targeted, resulting in a primary beam diameter full
width at half-maximum of 2.3°, and a resolution of
8.0"x6.0" in the final map. A total of 24h of observations were
scheduled during three nights. Due to the upgrade of some VLA
antennas, and the incompatibility of the P-band receivers with the
upgrade, about half of the data were lost, implying a total
integration time of ∼12h for a 27-antenna array.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
catalog.dat 208 182 90cm COSMOS source catalog
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See also:
VIII/92 : The FIRST Survey Catalog, Version 2014Dec17 (Helfand+ 2015)
J/AJ/128/1974 : The VLA-COSMOS survey. I. (Schinnerer+, 2004)
J/ApJS/172/46 : The VLA-COSMOS survey. II. (Schinnerer+, 2007)
J/ApJS/188/384 : The VLA-COSMOS survey. IV. (Schinnerer+, 2010)
Byte-by-byte Description of file: catalog.dat
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Bytes Format Units Label Explanations
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1- 13 A13 --- --- [COSMOSVLA327_]
14- 31 A18 --- Name COSMOSVLA327 name (HHMMSS.ss+DDMMSS.s, J2000)
33- 43 F11.7 deg RAdeg Source position RA (J2000)
45- 53 F9.7 deg DEdeg Source position DEC (J2000)
55- 56 I2 h RAh Right ascension (J2000)
58- 59 I2 min RAm Right ascension (J2000)
61- 66 F6.3 s RAs Right ascension (J2000)
68 A1 --- DE- Declination sign (J2000)
69- 70 I2 deg DEd Declination (J2000)
72- 73 I2 arcmin DEm Declination (J2000)
75- 80 F6.3 arcsec DEs Declination (J2000)
82- 87 F6.2 arcsec e_RAs [0.3/1.1]?=-99 rms error on right ascension (1)
89- 94 F6.2 arcsec e_DEs [0.4/1.1]?=-99 rms error on declination (1)
96-102 F7.3 mJy Fp [2/118]?=-99 327MHz peak flux of source
(in mJy/beam) (1)
104-110 F7.3 mJy e_Fp [0.2/5.6]?=-99 rms uncertainty on peak flux
(in mJy/beam) (1)
112-118 F7.3 mJy Ft [2/683] 327MHz integrated source flux density
120-126 F7.3 mJy e_Ft [0.2/17]?=-99 rms uncertainty on Ft
128-132 F5.3 mJy rms [0.3/6.3]?=-99 measured local rms at the radio
source position (in mJy/beam)
134-138 F5.2 arcsec bmaj [0/97] Deconvolved source major axis (2)
140-144 F5.2 arcsec bmin [0/34] Deconvolved source minor axis (2)
146-151 F6.2 deg PA [0/180]?=-99 Position angle (3)
153 I1 --- Res [0/1] 1=resolved source; 0=unresolved (2)
155 I1 --- Mult [0/1] 1=multi-component source (1), 0=no
157-187 A31 --- RName 20cm source name (4)
189-195 F7.3 mJy Fp20 ?=-88 20cm peak flux of source (in mJy/beam)
197-203 F7.3 mJy Ft20 ?=-88 20cm integrated source flux density
205-208 F4.2 arcsec Sep [0/9]?=- 20cm-90cm sources separation
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Note (1): value is -99.00 if multi-component source
Note (2): Major and Minor axis are 0.0 for unresolved sources
Note (3): Position angle is set to:
-99.0 = multi-component source,
0.00 = unresolved sources (bmaj = bmin = 0)
Note (4): 20cm names are:
* FIRSTVLAJHHMMSS.ss+DDMMSS.s : see VIII/92
* COSMOSVLADP_JHHMMSS.ss+DDMMSS.s : see J/ApJS/188/384
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History:
Copied at http://irsa.ipac.caltech.edu/data/COSMOS/tables/vla/
References:
Schinnerer et al., Paper I 2004AJ....128.1974S 2004AJ....128.1974S, Cat. J/AJ/128/1974
Schinnerer et al., Paper II 2007ApJS..172...46S 2007ApJS..172...46S, Cat. J/ApJS/172/46
Bondi et al., Paper III 2008ApJ...681.1129B 2008ApJ...681.1129B
Schinnerer et al., Paper IV 2010ApJS..188..384S 2010ApJS..188..384S, Cat. J/ApJS/188/384
(End) Patricia Vannier [CDS] 16-Apr-2015