The 9C Survey: a deeper source count at 15 GHz

TL;DR

The 9C Survey provides a deeper 15 GHz radio source count, improving understanding of foreground contamination for CMB measurements by extending the survey sensitivity from 25mJy to 5mJy.

Contribution

This is the first high-frequency radio survey at 15 GHz reaching a completeness limit of 5mJy, significantly deeper than previous surveys.

Findings

Extended source counts down to 5mJy at 15 GHz.

Improved data for foreground modeling in CMB observations.

Enhanced understanding of radio source populations at high frequencies.

Abstract

Foreground radio sources are a major contaminant for centimetre-wave cosmic microwave background (CMB) measurements and the 9C survey was set up as part of the observing strategy of the CMB telescope, the Very Small Array. Prior to this survey with the Ryle Telescope at 15 GHz there was no comparable high-frequency radio survey of any extent. Our first published source count reached a limit of ~25mJy but we have now surveyed some areas more deeply, to a completenesss limit of ~5mJy. We present the results from this deeper survey.