University of Hertfordshire

LOFAR/H-ATLAS: A deep low-frequency survey of the Herschel-ATLAS North Galactic Pole field

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Documents

• G. Gürkan
• R. J. van Weeren
• W. L. Williams
• P. N. Best
• F. de Gasperin
• D. A. Rafferty
• J. Sabater
• T. W. Shimwell
• C. Tasse
• N. Bourne
• M. Brienza
• M. Brüggen
• G. Brunetti
• K. T. Chyży
• J. Conway
• L. Dunne
• S. A. Eales
• M. J. Jarvis
• E. K. Mahony
• R. Morganti
• I. Prandoni
• H. J. A. Röttgering
• E. Valiante
• G. J. White
Original language English 1910-1936 27 Monthly Notices of the Royal Astronomical Society 463 1 20 Jul 2016 https://doi.org/10.1093/mnras/stw1763 Published - 21 Oct 2016

Abstract

We present LOFAR High-Band Array (HBA) observations of the Herschel-ATLAS North Galactic Pole survey area. The survey we have carried out, consisting of four pointings covering around 142 square degrees of sky in the frequency range 126--173 MHz, does not provide uniform noise coverage but otherwise is representative of the quality of data to be expected in the planned LOFAR wide-area surveys, and has been reduced using recently developed `facet calibration' methods at a resolution approaching the full resolution of the datasets ($\sim 10 \times 6$ arcsec) and an rms off-source noise that ranges from 100 $\mu$Jy beam$^{-1}$ in the centre of the best fields to around 2 mJy beam$^{-1}$ at the furthest extent of our imaging. We describe the imaging, cataloguing and source identification processes, and present some initial science results based on a 5-$\sigma$ source catalogue. These include (i) an initial look at the radio/far-infrared correlation at 150 MHz, showing that many Herschel sources are not yet detected by LOFAR; (ii) number counts at 150 MHz, including, for the first time, observational constraints on the numbers of star-forming galaxies; (iii) the 150-MHz luminosity functions for active and star-forming galaxies, which agree well with determinations at higher frequencies at low redshift, and show strong redshift evolution of the star-forming population; and (iv) some discussion of the implications of our observations for studies of radio galaxy life cycles.

Notes

© 2016 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. This is an Open Access article distributed under the terms of the Creative Commons Attribution License CC BY 4.0 (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.

• Hertfordshire Astronomy 2015-18

Project: Research

• LOFAR-UK Compute Facility 2016-2019

Project: Other

ID: 10289956