Milli-arcsecond properties of 10C sources in the Lockman Hole

Abstract

We have used recent Very Long Baseline Interferometry (VLBI) observations by Middelberg et al. with a resolution of $\approx 10$ mas to investigate the properties of faint sources selected from the Tenth Cambridge (10C) survey in the Lockman Hole. The 10C survey is complete to 0.5 mJy at 15.7 GHz and has a resolution of 30 arcsec. We have previously shown that this population is dominated by flat-spectrum sources below $\approx 1$ mJy, in disagreement with several models of the faint, high-frequency sky. We find that 33 out of the 51 10C sources in the VLBI field (65 percent) are detected by the VLBI observations. The sources detected by the VLBI observations must have a high brightness temperature, thus ruling out the possibility that this faint, high frequency population is dominated by starbursting or starforming sources and indicating that they must be Active Galactic Nuclei.

Accepted for publication in MNRAS

References in corpus (4)

• Radio and Mid-Infrared Properties of Compact Starbursts: Distancing Themselves from the Main Sequence
• A 610-MHz survey of the Lockman Hole with the Giant Metrewave Radio Telescope - I. Observations, data reduction and source catalogue for the central 5 square degrees
• The faint source population at 15.7 GHz - I. The radio properties
• The AT20G high angular resolution catalogue

Cited by in corpus (2)

• The faint source population at 15.7 GHz - III. A high-frequency study of HERGs and LERGs
• The faint radio source population at 15.7 GHz - II. Multi-wavelength properties