9C continued: results from a deeper radio-source survey at 15 GHz

The 9C survey of radio sources with the Ryle Telescope at 15.2 GHz was set up to survey the fields observed with the cosmic microwave background telescope, the Very Small Array. In our first paper, we described three regions of the survey, constituting a total area of 520 deg² to a completeness limit of ≈25 mJy. Here we report on a series of deeper regions, amounting to an area of 115 deg² complete to ≈10 mJy and of 29 deg² complete to ≈5.5 mJy. We have investigated the source counts and the distributions of the 1.4 to 15.2 GHz spectral indices (α^15.2_1.4) for these deeper samples. The whole catalogue of 643 sources is available online.