Based on observations collected at the European Organization for Astronomical Research in the Southern hemisphere, Chile, VIDEO: 179.A-2006.
The likelihood ratio as a tool for radio continuum surveys with Square Kilometre Array precursor telescopes
Article first published online: 3 MAY 2012
© 2012 The Authors Monthly Notices of the Royal Astronomical Society © 2012 RAS
Monthly Notices of the Royal Astronomical Society
Volume 423, Issue 1, pages 132–140, June 2012
How to Cite
McAlpine, K., Smith, D. J. B., Jarvis, M. J., Bonfield, D. G. and Fleuren, S. (2012), The likelihood ratio as a tool for radio continuum surveys with Square Kilometre Array precursor telescopes. Monthly Notices of the Royal Astronomical Society, 423: 132–140. doi: 10.1111/j.1365-2966.2012.20715.x
Based on observations obtained with MegaPrime/MegaCam, a joint project of CFHT and CEA/DAPNIA, at the Canada-France-Hawaii Telescope (CFHT) which is operated by the National Research Council (NRC) of Canada, the Institut National des Science de l’Univers of the Centre National de la Recherche Scientifique (CNRS) of France, and the University of Hawaii. This work is based in part on data products produced at TERAPIX and the Canadian Astronomy Data Centre as part of the Canada-France-Hawaii Telescope Legacy Survey, a collaborative project of NRC and CNRS.
- Issue published online: 30 MAY 2012
- Article first published online: 3 MAY 2012
- Accepted 2012 February 8. Received 2012 February 3; in original form 2011 December 22
- methods: statistical;
- radio continuum: galaxies
In this paper we investigate the performance of the likelihood ratio method as a tool for identifying optical and infrared counterparts to proposed radio continuum surveys with Square Kilometre Array (SKA) precursor and pathfinder telescopes. We present a comparison of the infrared counterparts identified by the likelihood ratio in the VISTA Deep Extragalactic Observations (VIDEO) survey to radio observations with 6, 10 and 15 arcsec resolution. We cross-match a deep radio catalogue consisting of radio sources with peak flux density >60 Jy with deep near-infrared data limited to Ks≲ 22.6. Comparing the infrared counterparts from this procedure to those obtained when cross-matching a set of simulated lower resolution radio catalogues indicates that degrading the resolution from 6 arcsec to 10 and 15 arcsec decreases the completeness of the cross-matched catalogue by approximately 3 and 7 per cent respectively. When matching against shallower infrared data, comparable to that achieved by the VISTA Hemisphere Survey, the fraction of radio sources with reliably identified counterparts drops from ∼89 per cent, at Ks≲ 22.6, to 47 per cent with Ks≲ 20.0. Decreasing the resolution at this shallower infrared limit does not result in any further decrease in the completeness produced by the likelihood ratio matching procedure. However, we note that radio continuum surveys with the MeerKAT and eventually the SKA, will require long baselines in order to ensure that the resulting maps are not limited by instrumental confusion noise.