The faint source population at 15.7 GHz - I. The radio properties

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dc.contributor.authorWhittam, I.
dc.contributor.authorRiley, J.
dc.contributor.authorJarvis, Matt
dc.contributor.authorGreen, D.A.
dc.contributor.authorPrandoni, I.
dc.contributor.authorGuglielmino, G.
dc.contributor.authorMorganti, R.
dc.contributor.authorRöttgering, H. J. A.
dc.contributor.authorGarrett, M. A.
dc.date.accessioned2017-07-24T07:10:40Z
dc.date.available2017-07-24T07:10:40Z
dc.date.issued2013
dc.description.abstractWe have studied a sample of 296 faint (>0.5 mJy) radio sources selected from an area of the Tenth Cambridge (10C) survey at 15.7 GHz in the Lockman Hole. By matching this catalogue to several lower frequency surveys (e.g. including a deep GMRT survey at 610 MHz, aWSRT survey at 1.4 GHz, NVSS, FIRST and WENSS) we have investigated the radio spectral properties of the sources in this sample; all but 30 of the 10C sources are matched to one or more of these surveys. We have found a significant increase in the proportion of flat-spectrum sources at flux densities below ≈1 mJy – the median spectral index between 15.7 GHz and 610 MHz changes from 0.75 for flux densities greater than 1.5 mJy to 0.08 for flux densities less than 0.8 mJy. This suggests that a population of faint, flat-spectrum sources are emerging at flux densities 1mJy. The spectral index distribution of this sample of sources selected at 15.7 GHz is compared to those of two samples selected at 1.4 GHz from FIRST and NVSS. We find that there is a significant flat-spectrum population present in the 10C sample which is missing from the samples selected at 1.4 GHz. The 10C sample is compared to a sample of sources selected from the SKADS Simulated Sky byWilman et al. and we find that this simulation fails to reproduce the observed spectral index distribution and significantly underpredicts the number of sources in the faintest flux density bin. It is likely that the observed faint, flat-spectrum sources are a result of the cores of Fanaroff–Riley type I sources becoming dominant at high frequencies. These results highlight the importance of studying this faint, high-frequency population.en_US
dc.description.accreditationWeb of Science
dc.identifier.citationWhittam, I. et al. (2013). The faint source population at 15.7 GHz - I. The radio properties. Monthly Notices of the Royal Astronomical Society, 429: 2080–2097en_US
dc.identifier.issn0035-8711
dc.identifier.urihttp://hdl.handle.net/10566/3094
dc.identifier.urihttp://dx.doi.org/10.1093/mnras/sts478
dc.language.isoenen_US
dc.publisherOxford University Pressen_US
dc.rightsCopyright the Authors. Authors may archive the published version in their institutional repository.
dc.source.urihttp://dx.doi.org/10.1093/mnras/sts478
dc.subjectGalaxies: activeen_US
dc.subjectGalaxies: starbursten_US
dc.subjectRadio continuum: galaxiesen_US
dc.titleThe faint source population at 15.7 GHz - I. The radio propertiesen_US
dc.typeArticleen_US

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