LOFAR 150-MHz observations of the Bootes field: catalogue and source counts
Journal article, 2016
We present the first wide area (19 deg(2)), deep (a parts per thousand 120-150 mu Jy beam(-1)), high-resolution (5.6 x 7.4 arcsec) LOFAR High Band Antenna image of the Bootes field made at 130-169 MHz. 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 6 276 sources detected over an area of 19 deg(2), with a peak flux density threshold of 5 sigma. As the first thorough test of the facet calibration strategy, introduced by van Weeren et al., 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.
radio continuum: galaxies
surveys
galaxies: active
techniques: interferometric
Author
W. L. Williams
Leiden University
Netherlands Institute for Radio Astronomy (ASTRON)
University of Hertfordshire
R. J. van Weeren
Harvard-Smithsonian Center for Astrophysics
H. Rottgering
Leiden University
P. Best
Royal Observatory
T. J. Dijkema
Netherlands Institute for Radio Astronomy (ASTRON)
F. De Gasperin
University of Hamburg
M. J. Hardcastle
University of Hertfordshire
G. Heald
University of Groningen
Netherlands Institute for Radio Astronomy (ASTRON)
I. Prandoni
Istituto nazionale di astrofisica (INAF)
J. Sabater
Royal Observatory
T. W. Shimwell
Leiden University
C. Tasse
Paris Diderot University
I. van Bemmel
Joint Institute for VLBI in Europe (JIVE)
M. Brüggen
University of Hamburg
G. Brunetti
Istituto nazionale di astrofisica (INAF)
John Conway
Chalmers, Earth and Space Sciences, Onsala Space Observatory
T.A. Enßlin
Max Planck Society
D. Engels
University of Hamburg
H. Falcke
Radboud University
Netherlands Institute for Radio Astronomy (ASTRON)
C. Ferrari
Observatoire de la Cote d'Azur
M. Haverkorn
Radboud University
Leiden University
N. Jackson
University of Manchester
M. J. Jarvis
University of Oxford
University of the Western Cape
A. D. Kapinska
University of Portsmouth
University of Western Australia
ARC Centre of Excellence for All-sky Astrophysics (CAASTRO)
E. Mahony
Netherlands Institute for Radio Astronomy (ASTRON)
G. K. Miley
Leiden University
L. K. Morabito
Leiden University
R. Morganti
Netherlands Institute for Radio Astronomy (ASTRON)
University of Groningen
E. Orru
Netherlands Institute for Radio Astronomy (ASTRON)
E. Retana-Montenegro
Leiden University
S. S. Sridhar
Netherlands Institute for Radio Astronomy (ASTRON)
University of Groningen
M. C. Toribio
Leiden University
G. J. White
STFC Rutherford Appleton Laboratory
Open University
M. W. Wise
Anton Pannekoek Institute for Astronomy
Netherlands Institute for Radio Astronomy (ASTRON)
J. T L Zwart
University of the Western Cape
University of Cape Town
Monthly Notices of the Royal Astronomical Society
0035-8711 (ISSN) 1365-2966 (eISSN)
Vol. 460 3 2385-2412Subject Categories (SSIF 2011)
Astronomy, Astrophysics and Cosmology
DOI
10.1093/mnras/stw1056