dc.contributor.author | Mahony, E. K. | |
dc.contributor.author | Morganti, R. | |
dc.contributor.author | Prandoni, I. | |
dc.contributor.author | Bemmel, I. M. van | |
dc.contributor.author | Shimwell, T. W. | |
dc.contributor.author | Brienza, M. | |
dc.contributor.author | Best, P. N. | |
dc.contributor.author | Brüggen, M. | |
dc.contributor.author | Rivera, G. Calistro | |
dc.contributor.author | Gasperin, F. de | |
dc.contributor.author | Hardcastle, M. J. | |
dc.contributor.author | Harwood, J. J. | |
dc.contributor.author | Heald, G. | |
dc.contributor.author | Jarvis, M. J. | |
dc.contributor.author | Mandal, S. | |
dc.contributor.author | Miley, G. K. | |
dc.contributor.author | Retana-Montenegro, E. | |
dc.contributor.author | Röttgering, H. J. A. | |
dc.contributor.author | Sabater, J. | |
dc.contributor.author | Tasse, C. | |
dc.contributor.author | Velzen, S. van | |
dc.contributor.author | Weeren, R. J. van | |
dc.contributor.author | Williams, W. L. | |
dc.contributor.author | White, G. J. | |
dc.date.accessioned | 2016-12-13T18:22:36Z | |
dc.date.available | 2016-12-13T18:22:36Z | |
dc.date.issued | 2016-12-11 | |
dc.identifier.citation | Mahony , E K , Morganti , R , Prandoni , I , Bemmel , I M V , Shimwell , T W , Brienza , M , Best , P N , Brüggen , M , Rivera , G C , Gasperin , F D , Hardcastle , M J , Harwood , J J , Heald , G , Jarvis , M J , Mandal , S , Miley , G K , Retana-Montenegro , E , Röttgering , H J A , Sabater , J , Tasse , C , Velzen , S V , Weeren , R J V , Williams , W L & White , G J 2016 , ' The Lockman Hole project : LOFAR observations and spectral index properties of low-frequency radio sources ' , Monthly Notices of the Royal Astronomical Society , vol. 463 , no. 3 , pp. 2297-3020 . https://doi.org/10.1093/mnras/stw2225 | |
dc.identifier.issn | 0035-8711 | |
dc.identifier.other | ArXiv: http://arxiv.org/abs/1609.00537v1 | |
dc.identifier.other | ORCID: /0000-0003-0251-6126/work/62748350 | |
dc.identifier.other | ORCID: /0000-0001-7315-1596/work/30425900 | |
dc.identifier.other | ORCID: /0000-0003-4223-1117/work/30390948 | |
dc.identifier.uri | http://hdl.handle.net/2299/17423 | |
dc.description | E. K. Mahoy, et al., 'The Lockman Hole project: LOFAR observations and spectral index properties of low-frequency radio sources' , the version of record [MNRAS (December 11, 2016) Vol 463 (3): 2997-3020, first published on line September 5, 2016, is available on line at doi: 10.1093/mnras/stw2225 Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved. | |
dc.description.abstract | The Lockman Hole is a well-studied extragalactic field with extensive multi-band ancillary data covering a wide range in frequency, essential for characterising the physical and evolutionary properties of the various source populations detected in deep radio fields (mainly star-forming galaxies and AGNs). In this paper we present new 150-MHz observations carried out with the LOw Frequency ARray (LOFAR), allowing us to explore a new spectral window for the faint radio source population. This 150-MHz image covers an area of 34.7 square degrees with a resolution of 18.6$\times$14.7 arcsec and reaches an rms of 160 $\mu$Jy beam$^{-1}$ at the centre of the field. As expected for a low-frequency selected sample, the vast majority of sources exhibit steep spectra, with a median spectral index of $\alpha_{150}^{1400}=-0.78\pm0.015$. The median spectral index becomes slightly flatter (increasing from $\alpha_{150}^{1400}=-0.84$ to $\alpha_{150}^{1400}=-0.75$) with decreasing flux density down to $S_{150} \sim$10 mJy before flattening out and remaining constant below this flux level. For a bright subset of the 150-MHz selected sample we can trace the spectral properties down to lower frequencies using 60-MHz LOFAR observations, finding tentative evidence for sources to become flatter in spectrum between 60 and 150 MHz. Using the deep, multi-frequency data available in the Lockman Hole, we identify a sample of 100 Ultra-steep spectrum (USS) sources and 13 peaked spectrum sources. We estimate that up to 21 percent of these could have $z>4$ and are candidate high-$z$ radio galaxies, but further follow-up observations are required to confirm the physical nature of these objects. | en |
dc.format.extent | 24 | |
dc.format.extent | 12094924 | |
dc.language.iso | eng | |
dc.relation.ispartof | Monthly Notices of the Royal Astronomical Society | |
dc.subject | astro-ph.GA | |
dc.subject | astro-ph.CO | |
dc.title | The Lockman Hole project : LOFAR observations and spectral index properties of low-frequency radio sources | en |
dc.contributor.institution | School of Physics, Astronomy and Mathematics | |
dc.contributor.institution | Centre for Astrophysics Research | |
dc.description.status | Peer reviewed | |
rioxxterms.versionofrecord | 10.1093/mnras/stw2225 | |
rioxxterms.type | Journal Article/Review | |
herts.preservation.rarelyaccessed | true | |