# GMRT 610-MHz observations of the faint radio source population – and what these tell us about the higher radio-frequency sky

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Publication Date: 2017-01-21

Journal Title: Monthly Notices of the Royal Astronomical Society

Publisher: Oxford University Press

Volume: 464

Issue: 3

Pages: 3357-3368

Language: English

Type: Article

This Version: VoR

Citation: Whittam, I., Green, D., Jarvis, M., & Riley, J. (2017). GMRT 610-MHz observations of the faint radio source population – and what these tell us about the higher radio-frequency sky. Monthly Notices of the Royal Astronomical Society, 464 (3), 3357-3368. https://doi.org/10.1093/mnras/stw2638

Abstract: We present 610-MHz Giant Metrewave Radio Telescope observations of 0.84 deg$^{2}$ of the AMI001 field (centred on 00$^{h}$23$^{m}$10$^{s}$, +31°53′) with an rms noise of 18 μJy beam$^{-1}$ in the centre of the field. A total of 955 sources are detected, and 814 are included in the source count analysis. The source counts from these observations are consistent with previous work. We have used these data to study the spectral index distribution of a sample of sources selected at 15.7 GHz from the recent deep extension to the Tenth Cambridge (10C) survey. The median spectral index, α, (where S ∝ ν$^{−α}$) between 0.08<$\textit{S}$$_{15.7GHz}$/mJy<0.2 is 0.32 ± 0.14, showing that star-forming galaxies, which have much steeper spectra, are not contributing significantly to this population. This is in contrast to several models, but in agreement with the results from the 10C ultradeep source counts; the high-frequency sky therefore continues to be dominated by radio galaxies down to S$_{15.7GHz}$ = 0.1 mJy.

Keywords: catalogues, surveys, galaxies: active, radio continuum: galaxies

Sponsorship: The GMRT is run by the National Centre for Radio Astrophysics of the Tata Institute of Fundamental Research. IHW thanks the Science and Technologies Facilities Council for a studentship. IHW and MJJ acknowledge support from the Square Kilometre Array South Africa. IHW thanks the South African Astronomical Observatory, where some of this work was carried out.

Embargo Lift Date: 2100-01-01

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External DOI: https://doi.org/10.1093/mnras/stw2638

This record's URL: https://www.repository.cam.ac.uk/handle/1810/261487

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Autor: Whittam, IH Green, DAJarvis, MJRiley, JM

Fuente: https://www.repository.cam.ac.uk/handle/1810/261487

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