Milliarcsecond properties of 10C sources in the Lockman Hole. Issue 1 (8th March 2014)

• Record Type: Journal Article
• Authors: Whittam, I. H.; Riley, J. M.; Green, D. A.
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 440:Issue 1(2014)
• Page Start: 40
• Page End: 49
• Publication Date: 2014-03-08
• Subjects: galaxies: active -- radio continuum: galaxies; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/stu290
• Languages: English
• ISSNs: 0035-8711

Abstract

Abstract: We have used recent very long baseline interferometry (VLBI) observations by Middelberg et al. with a resolution of ≈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 ≈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 per cent) 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.