J/A+A/602/A1 VLA-COSMOS 3 GHz Large Project (Smolcic+, 2017)
The VLA-COSMOS 3 GHz Large Project: Continuum data and source catalog release.
Smolcic V., Novak M., Bondi M., Ciliegi P., Mooley K.P., Schinnerer E.,
Zamorani G., Navarrete F., Bourke S., Karim A., Vardoulaki E., Leslie S.,
Delhaize J., Carilli C.L., Myers S.T., Baran N., Delvecchio I.,
Miettinen O., Banfield J., Balokovic M., Bertoldi F., Capak P., Frail D.A.,
Hallinan G., Hao H., Herrera Ruiz N., Horesh A., Ilbert O., Intema H.,
Jelic V., Klockner H-R., Krpan J., Kulkarni S.R., McCracken H., Laigle C.,
Middleberg E., Murphy E., Sargent M., Scoville N.Z., Sheth K.
<Astron. Astrophys. 602, A1 (2017)>
=2017A&A...602A...1S 2017A&A...602A...1S (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, radio ; Surveys
Keywords: galaxies: fundamental parameters - galaxies: active, evolution -
cosmology: observations - radio continuum: galaxies
Abstract:
We present the VLA-COSMOS 3GHz Large Project based on 384 hours of
observations with the Karl G. Jansky Very Large Array (VLA) at 3GHz
(10cm) toward the two square degree Cosmic Evolution Survey (COSMOS)
field. The final mosaic reaches a median rms of 2.3 uJy/beam over the
two square degrees at an angular resolution of 0.75". To fully account
for the spectral shape and resolution variations across the broad
(2GHz) band, we image all data with a multiscale, multifrequency
synthesis algorithm. We present a catalog of 10,830 radio sources down
to 5σ, out of which 67 are combined from multiple components.
Comparing the positions of our 3GHz sources with those from the Very
Long Baseline Array (VLBA)-COSMOS survey, we estimate that the
astrometry is accurate to 0.01" at the bright end (signal-to-noise
ratio, S/N3GHz>20). Survival analysis on our data combined with the
VLA-COSMOS 1.4GHz Joint Project catalog yields an expected median
radio spectral index of α=-0.7. We compute completeness
corrections via Monte Carlo simulations to derive the corrected 3GHz
source counts. Our counts are in agreement with previously derived
3GHz counts based on single-pointing (0.087 square degrees) VLA data.
In summary, the VLA-COSMOS 3GHz Large Project simultaneously provides
the largest and deepest radio continuum survey at high (0.75") angular
resolution to date, bridging the gap between last-generation and
next-generation surveys.
Description:
The catalog contains sources selected down to a
5σ(σ∼2.3uJy/beam) threshold. This catalog can be used for
statistical analyses, accompanied with the corrections given in the
data & catalog release paper. All completeness & bias corrections and
source counts presented in the paper were calculated using
this sample. The total fraction of spurious sources in the COSMOS 2
sq.deg. is below 2.7% within this catalog. However, an increase of
spurious sources up to 24% at 5.0<S/N<5.5 is present (for details
see Sec. 5.2., Fig. 17 and Table 3 of the paper). A subsample
with a minimal spurious source fraction can be selected by requiring
an additional cutoff S/N≥5.5 for single component sources
(MULTI=0). The total fraction of spurious sources in the COSMOS 2
sq.deg. within such a selected sample is below 0.4%, and the fraction
of spurious sources is below 3% even at the lowest S/N (=5.5).
Catalog Notes:
1. Maximum ID is 10966 although there are 10830 sources. Some IDs were
removed by joining them into multi-component sources.
2. Peak surface brightness of sources [uJy/beam] is not reported,
but can be obtained by multiplying SNR with RMS.
3. High NPIX usually indicates extended or very bright sources.
4. Reported positional errors on resolved and extended sources should be
considered lower limits.
5. Multicomponent sources have errors and S/N column values set to -99.0
Additional data information:
Catalog date: 21-Mar-2016
Source extractor: BLOBCAT v1.2 (http://blobcat.sourceforge.net/)
Observations: 384 hours, VLA, S-band (2-4GHz), A+C array, 192 pointings
Imaging software: CASA v4.2.2 (https://casa.nrao.edu/)
Imaging algorithm: Multiscale multifrequency synthesis on single pointings
Mosaic size: 30000x30000 pixels (3.3 GB)
Pixel size: 0.2x0.2 arcsec2
Median rms noise in the COSMOS 2 sq.deg.: 2.3uJy/beam
Beam is circular with FWHM=0.75 arcsec
Bandwidth-smearing peak correction: 0% (no corrections applied)
Resolved criteria: Sint/Speak>1+6*snr^(-1.44)
Total area covered: 2.6 sq.deg.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 107 10830 VLA-COSMOS 3GHz radio catalog
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See also:
II/284 : COSMOS Multi-Wavelength Photometry Catalog (Capak+, 2007)
J/ApJ/644/100 : SDSS quasars in the COSMOS field (Prescott+, 2006)
J/ApJS/172/523 : COSMOS field Lyα emitters at z∼5.7 (Murayama+, 2007)
J/ApJS/172/368 : XMM-Newton survey in COSMOS field. IV. (Mainieri+, 2007)
J/ApJS/175/128 : Hα emitting galaxies in COSMOS-2 field (Shioya+, 2008)
J/MNRAS/385/2225 : AzTEC millimetre survey of COSMOS field (Scott+, 2008)
J/ApJS/184/158 : Chandra COSMOS survey I. (Elvis+, 2009)
J/A+A/497/635 : XMM wide-field survey in COSMOS field (Cappelluti+, 2009)
J/AJ/138/1261 : Spitzer/MIPS observations of the COSMOS field (Frayer+ 2009)
J/ApJ/709/572 : COSMOS 70um sources (Kartaltepe+, 2010)
J/ApJ/716/348 : The XMM-Newton survey of the COSMOS field (Brusa+, 2010)
J/ApJ/760/128 : COSMOS 4<z<6 sources Lyα emission (Mallery+, 2012)
J/MNRAS/436/1919 : SCUBA observations of COSMOS galaxies (Casey+, 2013)
J/A+A/567/A76 : COSMOS field radio-loud AGN population at z>1 (Baldi+, 2014)
J/ApJ/819/62 : The COSMOS-Legacy Survey (CLS) catalog (Civano+, 2016)
J/AJ/128/1974 : The VLA-COSMOS survey (Schinnerer+, 2004)
J/ApJS/172/46 : VLA-COSMOS survey. II. (Schinnerer+, 2007)
J/ApJS/188/384 : The VLA-COSMOS survey. IV. (Schinnerer+, 2010)
J/MNRAS/443/2590 : The VLA-COSMOS Survey. V. 324MHz (Smolcic+, 2014)
J/A+A/602/A2 : VLA-COSMOS 3GHz Large Project. II. (Smolcic+, 2017)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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2- 6 I5 --- ID Numerical ID of the source (1)
8- 17 A10 --- --- [COSMOSVLA3]
19- 37 A19 --- COSMOSVLA3 COSMOSVLA3 name (JHHMMSS.ss+DDMMSS.s)
39- 48 F10.6 deg RAdeg Right ascension (J2000)
50- 54 F5.3 arcsec e_RAdeg ?=9.999 Positional error in RAdeg (4)
56- 63 F8.6 deg DEdeg Declination (J2000)
65- 69 F5.3 arcsec e_DEdeg ?=9.999 Positional error in DEdeg (4)
71- 77 F7.1 uJy Flux Total integrated flux density at 3GHz (2)
79- 83 F5.1 uJy e_Flux ?=-99.0 Error on the total integrated
flux density
85- 89 F5.2 uJy/beam rms Local rms noise at the source position
91- 97 F7.2 --- SNR ?=-99.0 Signal-to-noise ratio (S/N) (5)
99-103 I5 --- Npix Number of pixels used for flux
integration (3)
105 I1 --- Res [0/1] Resolved flag (1 for yes)
107 I1 --- Multi [0/1] Multi-component flag (1 for yes)
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Note (1): Maximum ID is 10966 although there are 10830 sources. Some IDs were
removed by joining them into multi-component sources.
Note (2): Peak surface brightness of sources [uJy/beam] is not reported,
but can be obtained by multiplying SNR with rms.
Note (3): High NPIX usually indicates extended or very bright sources.
Note (4): Reported positional errors on resolved and extended sources should
be considered lower limits.
Note (5): Multicomponent sources have errors and S/N column values
set to -99.0.
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Acknowledgements:
Mladen Novak, mlnovak(at)phy.hr
References:
Smolcic et al., Paper II 2017A&A...602A...2S 2017A&A...602A...2S, Cat. J/A+A/602/A2
Delvecchio et al., Paper III 2017A&A...602A...3D 2017A&A...602A...3D
Delhaize et al., Paper IV 2017A&A...602A...4D 2017A&A...602A...4D
Novak et al., Paper V 2017A&A...602A...5N 2017A&A...602A...5N
Smolcic et al., Paper VI 2017A&A...602A...6S 2017A&A...602A...6S
(End) Patricia Vannier [CDS] 20-Oct-2016