J/MNRAS/460/2385 Bootes field LOFAR 150-MHz observations (Williams+, 2016)
LOFAR 150-MHz observations of the Bootes field: catalogue and source counts.
Williams W.L., van Weeren R.J., Rottgering H.J.A., Best P., Dijkema T.J.,
de Gasperin F., Hardcastle M.J., Heald G., Prandoni I., Sabater J.,
Shimwell T.W., Tasse C., van Bemmel I.M., Bruggen M., Brunetti G.,
Conway J.E., Ensslin T., Engels D., Falcke H., Ferrari C., Haverkorn M.,
Jackson N., Jarvis M.J., Kapinska A.D., Mahony E.K., Miley G.K.,
Morabito L.K., Morganti R., Orru E., Retana-Montenegro E., Sridhar S.S.,
Toribio M.C., White G.J., Wise M.W., Zwart J.T.L.
<Mon. Not. R. Astron. Soc., 460, 2385-2412 (2016)>
=2016MNRAS.460.2385W 2016MNRAS.460.2385W (SIMBAD/NED BibCode)
ADC_Keywords: Surveys ; Galaxies, radio ; Radio continuum
Keywords: techniques: interferometric - surveys - galaxies: active -
radio continuum: galaxies
Abstract:
We present the first wide area (19 deg2), deep (~=120-150
µJy/beam), high-resolution (5.6x7.4-arcsec) LOFAR High Band Antenna
image of the Bootes field made at 130-169MHz. This image is at least
an order of magnitude deeper and 3-5 times higher in angular
resolution than previously achieved for this field at low frequencies.
The observations and data reduction, which includes full
direction-dependent calibration, are described here. We present a
radio source catalogue containing 6276 sources detected over an area
of 19deg2, with a peak flux density threshold of 5σ. As the
first thorough test of the facet calibration strategy, introduced by
van Weeren et al. (2016ApJS..223....2V 2016ApJS..223....2V), we investigate the flux and
positional accuracy of the catalogue. We present differential source
counts that reach an order of magnitude deeper in flux density than
previously achieved at these low frequencies, and show flattening at
150-MHz flux densities below 10 mJy associated with the rise of the
low flux density star-forming galaxies and radio-quiet AGN.
Description:
Here, we report on the first LOFAR Cycle 2 High Band Antenna (HBA)
observations of the Bootes field. The Bootes field is one of the
Tier-3 Survey fields, and the aim is to eventually survey this field
to the extreme rms depth of 12uJy/beam (1σ) at 150MHz.
The Bootes field was observed on 2014 August 10 with the LOFAR HBA
stations.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 108 6276 LOFAR 150-MHz source catalogue
table2.fits 2880 250 Fits version of table 2
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See also:
J/AJ/123/1784 : 1.4 GHz imaging of the Bootes field (de Vries+, 2002)
J/AJ/127/213 : LALA Bootes field X-ray source catalog (Wang+, 2004)
J/AJ/130/923 : Faint radio sources in the NOAO Bootes field (Wrobel+, 2005)
J/ApJ/634/L1 : 16µm sources in the NOAO Bootes field (Kasliwal+, 2005)
J/ApJS/161/9 : X-ray survey of the NDWFS Bootes field (Kenter+, 2005)
J/ApJ/641/140 : Optical counterparts in NDWFS Bootes field (Brand+, 2006)
J/A+A/535/A38 : Observations of NOAO Bootes field at 153MHz (Intema+, 2011)
J/ApJ/772/26 : AGN with WISE. II. The NDWFS Bootes field (Assef+, 2013)
J/A+A/549/A55 : GMRT 153MHz (2m) Radio Mini Survey I. (Williams+, 2013)
J/MNRAS/450/1477 : VLA 352MHz image of the Bootes field. I. (Coppejans+, 2015)
J/ApJ/817/119 : Spitzer/IRAC variability survey of Bootes field
(Kozlowski+, 2016)
J/ApJ/793/82 : LOFAR Bootes and 3C295 field sources (van Weeren+, 2014)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 19 A19 --- Name LOFAR name (JHHMMSS.ss+DDMMSS.s)
(LOFAR_name)
21- 29 F9.5 deg RAdeg Flux-weighted right ascension (J2000) (RA)
31- 37 F7.5 deg e_RAdeg rms uncertainty on RAdeg (E_RA)
39- 47 F9.5 deg DEdeg Flux-weighted declination (J2000) (DEC)
49- 55 F7.5 deg e_DEdeg rms uncertainty on DEdeg (E_DEC)
57- 63 F7.2 mJy Sint Integrated source flux density at 150MHz
(Total_flux)
65- 69 F5.2 mJy e_Sint rms uncertainty on Sint (ETotalflux)
71- 77 F7.2 mJy/beam Fpeak Peak flux density at 150MHz (Peak_flux)
79- 83 F5.2 mJy/beam e_Fpeak rms uncertainty on Fpeak (EPeakflux)
85- 88 F4.2 --- Fsmear Approximate correction factor to the peak
flux density to account for bandwidth- and
time-smearing (Fsmear)
90- 93 F4.2 mJy/beam rms Local rms noise used for the source
detection (rms)
95- 96 I2 --- Ngauss Number of Gaussian components (Ngauss)
98 I1 --- Resolved [0/1] flag indicating the resolved
parametrization of the source
(Flag_resolved) (1)
100 I1 --- Badfit [0/1] a bad Gaussian fit and so no
parameters derived from the Gaussian
fit (Flag_badfit)
102 I1 --- Edge [0/1] a source on the edge of the mosaic
such that some of the flux is missing
(Flag_edge)
104 I1 --- Bad [0/1] a source has been successfully fit
with Gaussians but visual inspection
indicates a likely poor fit or other
problem (Flag_bad)
106 I1 --- Artefact [0/2] a source is identified as an
artefact (Flag_artefact) (2)
108 I1 --- Merged [0/1] a large source whose source
components have been manually merged into
single sources (Flag_merged)
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Note (1): flag indicating the resolved parametrization of the source as follows:
0 = unresolved sources
1 = resolved sources
Note (2): artefact flag as follows:
0 = no artefact
1 = a likely artefact
2 = an almost certain artefact
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 15-Nov-2017