The VLA-VIRMOS Deep Field

I. Radio observations probing the μJy source population

¹ Istituto di Radioastronomia del CNR, Via Gobetti 101, 40129 Bologna, Italy
² Osservatorio Astronomico di Bologna, Via Ranzani 1, 40127, Bologna, Italy
³ Università degli Studi di Bologna, Dipartimento di Fisica, Viale Berti Pichat 6/2, 40127 Bologna, Italy
⁴ Laboratoire d'Astrophysique de Marseille, Traverse du Siphon-Les trois Lucs, BP 8, 13376 Marseille Cedex 12, France
⁵ Osservatorio Astronomico di Capodimonte, Via Moiariello 16, 80127, Napoli, Italy
⁶ Osservatorio Astronomico di Brera, Via Brera 28, 20121 Milano, Italy
⁷ Istituto di Astrofisica Spaziale e Fisica Cosmica del CNR, Via Bassini 15, 20133 Milano, Italy
⁸ Osservatorio Astronomico di Roma, Via Osservatorio 2, 00040, Monteporzio Catone (Roma), Italy
⁹ Università degli Studi di Bologna, Dipartimento di Astronomia, Via Ranzani 1, 40127 Bologna, Italy

Corresponding author: M. Bondi, bondi@ira.cnr.it

Received: 16 December 2002
Accepted: 5 March 2003

Abstract

We have conducted a deep survey (rms noise Jy) with the Very Large Array (VLA) at 1.4 GHz, with a resolution of 6 arcsec, of a 1 deg² region included in the VIRMOS VLT Deep Survey. In the same field we already have multiband photometry down to , and spectroscopic observations will be obtained during the VIRMOS VLT survey. The homogeneous sensitivity over the whole field has allowed to derive a complete sample of 1054 radio sources ( limit). We give a detailed description of the data reduction and of the analysis of the radio observations, with particular care to the effects of clean bias and bandwidth smearing, and of the methods used to obtain the catalogue of radio sources. To estimate the effect of the resolution bias on our observations we have modelled the effective angular-size distribution of the sources in our sample and we have used this distribution to simulate a sample of radio sources. Finally we present the radio count distribution down to 0.08 mJy derived from the catalogue. Our counts are in good agreement with the best fit derived from earlier surveys, and are about 50% higher than the counts in the HDF. The radio count distribution clearly shows, with extremely good statistics, the change in the slope for the sub-mJy radio sources.