Radio Observations of the Marano Field: Sub-Millijansky Source Counts and Spectral Index Studies

Abstract

The Marano Field (centered at α(2000)=03h15m09sδ(2000)= −55° 13′ 57″) is a deep ROSAT field (flux limit ≃ 4 × 10–15erg cm–2s–1), which has been entirely covered by ESO 3.6 m plates and in the inner part by deep CCD exposures. In order to follow up these data in other wavelength regions, deep radio observations of this field have been carried out with the Australia Telescope Compact Array (ATCA) at 1.370 and 2.378 GHz. The minimum reached rms noise value is ≃42 μJy at both frequencies. 80 and 45 sources form complete samples above 5.5 σlocallevel at 1.370 and 2.378 GHz respectively, in a square area of ≃0.34 sq. deg. Almost all of the sources detected at 2.378 GHz have been detected also at 1.370 GHz.