J/MNRAS/461/4151 KGS EoR0 Catalogue (Carroll+, 2016)
A high reliability survey of discrete Epoch of Reionization foreground sources
in the MWA EoR0 field.
Carroll P.A., Line J., Morales M.F., Barry N., Beardsley A.P.,
Hazelton B.J., Jacobs D.C., Pober J.C., Sullivan I.S., Webster R.L.,
Bernardi G., Bowman J.D., Briggs F., Cappallo R.J., Corey B.E.,
De Oliveira-Costa A., Dillon J.S., Emrich D., Ewall-Wice A., Feng L.,
Gaensler B.M., Goeke R., Greenhill L.J., Hewitt J.N., Hurley-Walker N.,
Johnston-Hollitt M., Kaplan D.L., Kasper J.C., Kim HS., Kratzenberg E.,
Lenc E., Loeb A., Lonsdale C.J., Lynch M.J., Mckinley B., Mcwhirter S.R.,
Mitchell D.A., Morgan E., Neben A.R., Oberoi D., Offringa A.R., Ord S.M.,
Paul S., Pindor B., Prabu T., Procopio P., Riding J., Rogers A.E.E.,
Roshi A., Udaya Shankar N., Sethi S.K., Srivani K.S., Subrahmanyan R.,
Tegmark M., Thyagarajan N., Tingay S.J., Trott C.M., Waterson M.,
Wayth R.B., Whitney A.R., Williams A., Williams C.L., Wu C., Wyithe J.S.B.
<Mon. Not. R. Astron. Soc., 461, 4151-4175 (2016)>
=2016MNRAS.461.4151C 2016MNRAS.461.4151C (SIMBAD/NED BibCode)
ADC_Keywords: Surveys ; Radio sources
Keywords: catalogues
Abstract:
Detection of the epoch of reionization HI signal requires a precise
understanding of the intervening galaxies and AGN, both for
instrumental calibration and foreground removal. We present a
catalogue of 7394 extragalactic sources at 182MHz detected in the
RA=0 field of the Murchison Widefield Array Epoch of Reionization
observation programme. Motivated by unprecedented requirements for
precision and reliability we develop new methods for source finding
and selection. We apply machine learning methods to self-consistently
classify the relative reliability of 9490 source candidates. A subset
of 7466 are selected based on reliability class and signal-to-noise
ratio criteria. These are statistically cross-matched to four other
radio surveys using both position and flux density information. We
find 7369 sources to have confident matches, including 90 partially
resolved sources that split into a total of 192 sub-components. An
additional 25 unmatched sources are included as new radio detections.
The catalogue sources have a median spectral index of -0.85. Spectral
flattening is seen towards lower frequencies with a median of -0.71
predicted at 182MHz. The astrometric error is 7-arcsec compared to a
2.3-arcmin beam FWHM. The resulting catalogue covers ∼1400deg2
and is complete to approximately 80mJy within half beam power. This
provides the most reliable discrete source sky model available to date
in the MWA EoR0 field for precision foreground subtraction.
Description:
The MWA EoR0 field is centred at RA=0h and Dec=-27°, and was
chosen because it has no bright complex sources in the primary field
of view. The FWHM of the antenna beam is approximately 20°, but
sources in the edges of the beam and first few side lobes are clearly
visible and should be subtracted (Thyagarajan et al.,
2015ApJ...804...14T 2015ApJ...804...14T, 2015ApJ...807L..28T 2015ApJ...807L..28T; Pober et al.,
2016ApJ...819....8P 2016ApJ...819....8P). For this catalogue we concentrate on identifying
sources in the primary beam but go out to the 5 per cent power point
(nearly first beam null, ∼1400deg2). The data for this catalogue
include 752min snapshot observations (112s consecutive integrations
with 8s gaps) from the night of 2013 August 23. The observations were
made at 182MHz with 31MHz bandwidth and cover 2.5h in total.
This process for source finding, measurement, and classification has
been termed KATALOGSS (KDD Astrometry, Trueness, and Apparent
Luminosity of Galaxies in Snapshot Surveys; hereafter abbreviated to
KGS).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
kgs.dat 426 7394 KGS catalogue
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See also:
VIII/16 : Molonglo Reference Catalogue of Radio Sources (Large+ 1991)
VIII/65 : 1.4GHz NRAO VLA Sky Survey (NVSS) (Condon+ 1998)
VIII/81 : Sydney University Molonglo Sky Survey (SUMSS V2.1) (Mauch+ 2008)
VIII/97 : 74MHz VLA Low-frequency Sky Survey Redux (VLSSr) (Lane+, 2014)
Byte-by-byte Description of file: kgs.dat
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Bytes Format Units Label Explanations
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1- 18 A18 --- Name Source name (KGS JHHMMSS+DDMMSS)
20- 29 F10.6 deg RAdeg Corrected mean J2000 right ascension of the
snapshot detection
31- 40 F10.6 deg DEdeg Corrected mean J2000 declination of the
snapshot detection
42- 51 F10.6 arcsec e_RAdeg Standard deviation of the measured
right ascension
53- 62 F10.6 arcsec e_DEdeg Standard deviation of the measured
declination
64- 72 F9.6 Jy S182 Weighted mean integrated 182MHz flux density
74- 81 F8.6 Jy e_S182 Standard deviation of the measured flux
density at 183MHz
83- 90 F8.6 --- EBcorr Estimated flux density correction factor for
Eddington Bias
92- 95 F4.2 --- RClass [0/9] Reliability classification (1)
97-102 F6.4 --- Beam [0/1] Mean relative beam response at the
source location
104-105 I2 --- Ndet Number of snapshots the source was detected in
107-114 A8 --- Match Type of match (2)
116 A1 --- Flag [0-2] Inspected flag (3)
118-125 F8.4 deg RAMdeg ? J2000 right ascension of the catalogue match
to NVSS or SUMSS
127-134 F8.4 deg DEMdeg ? J2000 declination of the catalogue match
to NVSS or SUMSS
136-140 F5.2 arcsec e_RAMdeg ? Uncertainty in right ascension of the NVSS
or SUMSS catalogue match
142-146 F5.2 arcsec e_DEMdeg ? Uncertainty in declination of the NVSS or
SUMSS catalogue match
148-153 F6.3 --- SI ? Spectral index α from a power-law
spectral index fit S∝να
to all catalogue matches
155-159 F5.3 --- e_SI ? Error on the spectral index parameter
161-165 F5.2 Jy S74 ? Flux density at 74MHz of the VLSSr
(Cat. VIII/97) catalogue match
167-172 F6.4 Jy e_S74 ? VLSSr flux density error
174-178 F5.2 Jy S408 ? Flux density at 408MHz of the MRC
(Cat. VIII/16) catalogue match
180-183 F4.2 Jy e_S408 ? MRC flux density error
185-190 F6.4 Jy S843 ? Flux density at 843MHz of the SUMSS
(Cat. VIII/81) catalogue match
192-197 F6.4 Jy e_S843 ? SUMSS flux density error
199-204 F6.4 Jy S1400 ? Flux density at 1.4GHz of the NVSS
(Cat. VIII/65) catalogue match
206-211 F6.4 Jy e_S1400 ? NVSS flux density
213-271 A59 --- VLSSr VLSSr (VIII/97) source name (JHHMMSS+DDMMSS)
273-281 A9 --- MRC MRC (VIII/16) source name (HHMM+DDd)
283-356 A74 --- SUMSS SUMSS (VIII/81) source name (JHHMMSS+DDMMSS)
358-426 A69 --- NVSS NVSS (VIII/65) source name (HHMMSS+DDMMSS)
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Note (1): 0 are the most reliable and 9 the least.
Note (2): Type of match are isolated, dominant, multiple, combine, or none.
Note (3): Inspected flag as follows:
0 = not visually inspected
1 = the catalogue data and images were inspected
2 = the match was modified by the authors
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 30-Jan-2018