The Parkes quarter-Jansky flat-spectrum sample^*

I. Sample selection and source identifications

¹ Research School of Astronomy & Astrophysics, The Australian National University, Mount Stromlo Observatory, Canberra, Australia
² Department of Astrophysics, University of Oxford, Nuclear and Astrophysics Laboratory, Keble Road, Oxford OX1 3RH, UK
³ European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching bei München, Germany
⁴ National Radio Astronomy Observatory, Edgemont Road, Charlottesville, VA 22903-2475, USA
⁵ Royal Observatory, Blackford Hill, Edinburgh EH3 9HJ, UK

Corresponding author: C. A. Jackson, cjackson@mso.anu.edu.au

Received: 7 November 2001
Accepted: 22 January 2002

Abstract

We present a new sample of quarter-Jansky flat-spectrum radio sources selected to search for high-redshift quasars and to study the evolution of the flat-spectrum quasar population. The sample comprises 878 radio sources selected from the Parkes catalogues with spectral indices 0.4 where . The sample covers all right ascensions and the declination range from to , excluding low galactic latitudes () and the Magellanic Cloud regions. We have obtained improved radio source positions, firstly to reconfirm the majority of the existing identifications, and secondly, using digitized sky-survey data and deep B, Gunn-i and Gunn-z CCD-imaging, to find optical identifications for 223 previously-unidentified sources. We present the final catalogue of 878 flat-spectrum sources: 827 are compact radio sources identified with galaxies, quasars and BL Lac objects, 38 have either extended radio structure or are identified with Galactic objects (PN, HII or non-compact radio source), 4 are obscured by Galactic stars, and 9 (1 per cent of the total sample) remain unidentified.