TY - GEN
T1 - Ultra steep spectrum radio sources in the Lockman Hole : SERVS identifications and redshift distribution at the faintest radio fluxes
AU - Bizzocchi, L.
AU - Afonso, J.
AU - Ibar, E.
AU - Grossi, M.
AU - Simpson, C.
AU - Chapman, S.
AU - Jarvis, M. J.
AU - Rottgering, H.
AU - Norris, R. P.
AU - Dunlop, J.
AU - Ivison, R. J.
AU - Messias, H.
AU - Pforr, J.
AU - Vaccari, M.
AU - Seymour, N.
AU - Best, P.
AU - Gonz, E.
AU - Farrah, D..
AU - Huang, J.-S.
AU - Lacy, M.
PY - 2012
Y1 - 2012
N2 - 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.
AB - 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.
UR - http://handle.uws.edu.au:8081/1959.7/552148
UR - http://www.jenam2010.org/
U2 - 10.1007/978-3-642-22795-0-10
DO - 10.1007/978-3-642-22795-0-10
M3 - Conference Paper
SN - 9783642227943
SP - 97
EP - 100
BT - The Square Kilometre Array: Paving the Way for the New 21st Century Radio Astronomy Paradigm: Proceedings of Symposium 7 of JENAM 2010, Lisbon, Portugal, 6-10 September 2010
PB - Springer
T2 - JENAM (Conference)
Y2 - 6 September 2010
ER -