Keck spectroscopy of z=1-3 ULIRGs from the Spitzer SWIRE survey

Simple item page
dc.creatorBerta, S.
dc.creatorLonsdale, C. J.
dc.creatorSiana, B.
dc.creatorFarrah, D.
dc.creatorSmith, H. E.
dc.creatorPolletta, M.
dc.creatorFranceschini, A.
dc.creatorFritz, J.
dc.creatorPerez-Fournon, I.
dc.creatorRowan-Robinson, M.
dc.creatorShupe, D.
dc.creatorSurace, J.
dc.date2007-03-09
dc.date.accessioned2026-07-07T12:53:42Z
dc.date.available2026-07-07T12:53:42Z
dc.description(Abridged) High-redshift ultra luminous infrared galaxies contribute the bulk of the cosmic IR background and are the best candidates for very massive galaxies in formation at z>1.5. We present Keck/LRIS optical spectroscopy of 35 z>1.4 luminous IR galaxies in the Spitzer Wide-area Infra-Red Extragalactic survey (SWIRE) northern fields (Lockman Hole, ELAIS-N1, ELAIS-N2). The primary targets belong to the ``IR-peak'' class of galaxies, having the 1.6 micron (restframe) stellar feature detected in the IRAC Spitzer channels.The spectral energy distributions of the main targets are thoroughly analyzed, by means of spectro-photometric synthesis and multi-component fits (stars + starburst dust + AGN torus). The IR-peak selection technique is confirmed to successfully select objects above z=1.4, though some of the observed sources lie at lower redshift than expected. Among the 16 galaxies with spectroscopic redshift, 62% host an AGN component, two thirds being type-1 and one third type-2 objects. The selection, limited to r'<24.5, is likely biased to optically-bright AGNs. The SEDs of non-AGN IR-peakers resemble those of starbursts (SFR=20-500 Msun/yr) hosted in massive (M>1e11 Msun) galaxies. The presence of an AGN component provides a plausible explanation for the spectroscopic/photometric redshift discrepancies, as the torus produces an apparent shift of the peak to longer wavelengths. These sources are analyzed in IRAC and optical-IR color spaces. In addition to the IR-peak galaxies, we present redshifts and spectral properties for 150 objects, out of a total of 301 sources on slits.
dc.descriptionAccepted for publications on Astronomy and Astrophysics (acceprance date March 8th, 2007). 33 pages. The quality of some figures have been degraded
dc.identifierhttps://arxiv.org/abs/astro-ph/0703214
dc.identifierhttp://arxiv.org/abs/astro-ph/0703214
dc.identifierAstron.Astrophys.467:565-584,2007
dc.identifierdoi:10.1051/0004-6361:20066795
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/223710
dc.subjectAstrophysics
dc.titleKeck spectroscopy of z=1-3 ULIRGs from the Spitzer SWIRE survey
dc.typetext

Files

Collections

arXiv