Ultra steep spectrum radio sources in the Lockman Hole: SERVS identifications and redshift distribution at the faintest radio fluxes

Bizzocchi, L.; Afonso, J.; Ibar, E.; Grossi, M.; Simpson, C.; Chapman, S.; Jarvis, M.; Rottgering, H.; Norris, R.; Dunlop, J.; Ivison, R.; Messias, H.; Pforr, J.; Vaccari, M.; Seymour, Nick; Best, P.; Gonz, E.; Farrah, D.; Huang, J.; Lacy, M.; Marastron, C.; Marchetti, L.; Mauduit, J.; Oliver, S.; Rigopoulou, D.; Stanford, S.; Surace, J.; Zeimann, G.

doi:10.1007/978-3-642-22795-0_10

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Authors

Bizzocchi, L.

Afonso, J.

Ibar, E.

Grossi, M.

Simpson, C.

Chapman, S.

Jarvis, M.

Rottgering, H.

Norris, R.

Dunlop, J.

Ivison, R.

Messias, H.

Pforr, J.

Vaccari, M.

Seymour, Nick

Best, P.

Gonz, E.

Farrah, D.

Huang, J.

Lacy, M.

Marastron, C.

Marchetti, L.

Mauduit, J.

Oliver, S.

Rigopoulou, D.

Stanford, S.

Surace, J.

Zeimann, G.

Date

2012

Type

Conference Paper

Metadata

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Citation

Bizzocchi, L. and Afonso, J. and Ibar, E. and Grossi, M. and Simpson, C. and Chapman, S. and Jarvis, M. et al. 2012. Ultra steep spectrum radio sources in the Lockman Hole: SERVS identifications and redshift distribution at the faintest radio fluxes, in Barbosa, D. and Anton, S. and Gurvits, L. and Maia, D. (ed.), The Square Kilometre Array: Paving the way for the new 21st century radio astronomy paradigm: Proceedings of Symposium 7 of JENAM 2010, pp. 97-100. Springer.

Source Title

Astrophysics and Space Science Proceedings

DOI

10.1007/978-3-642-22795-0_10

ISBN

9783642227943

School

Department of Physics and Astronomy

URI

http://hdl.handle.net/20.500.11937/17479

Collection

Curtin Research Publications

Abstract

Ultra Steep Spectrum (USS) radio sources have been successfully used to select powerful radio sources at high redshifts (z > 2). Typically restricted to large-sky surveys and relatively bright radio flux densities, it has gradually become possible to extend the USS search to sub-mJy levels, thanks to the recent appearance of sensitive low-frequency radio facilities. Here we present a first detailed analysis of the nature of the faintest USS sources. By using GMRT and VLA radio observations of the Lockman Hole (LH) at 610MHz and 1.4GHz, a sample of 58 micro-Jansky USS sources is assembled. Deep infrared data at 3.6 and 4.5µm from the Spitzer Extragalactic Representative Volume Survey (SERVS) is used to reliably identify counterparts for 48 (83%) of these sources, showing an average magnitude of [3.6]=19.7 mag(AB). Spectroscopic redshifts for 14 USS sources, together with photometric redshift estimates, improved by the use of the deep SERVS data, for a further 19 objects, show redshifts ranging from z =0.1 to z=2.8, peaking at z~0.6 and tailing off at high redshifts.