Back to Volume
Paper: Understanding Infrared Galaxy Populations: the SWIRE Legacy Survey
Volume: 381, The Second Annual Spitzer Science Center Conference: Infrared Diagnostics of Galaxy Evolution
Page: 216
Authors: Rowan-Robinson, M.; Lonsdale, C.; Smith, G.; Surace, J.; Shupe, D.; Polletta, M.; Siana, B.; Babbedge, T.; Oliver, S.; Perez-Fournon, I.; Franceschini, A.; Afonso A.; Luis, Clements, D.; Davoodi, P.; Domingue, D.; Efstathiou, A.; Fang, F.; Farrah, D.; Frayer, D.; Hatziminaoglou, E.; Gonzalez-Solares, E.; Xu, K.; Padgett, D.; Vaccari, M.
Abstract: We discuss spectral energy distributions, photometric redshifts, redshift distributions, luminosity functions, source-counts and the far infrared to optical luminosity ratio for sources in the SWIRE Legacy Survey.

The spectral energy distributions of selected SWIRE sources are modelled in terms of a simple set of galaxy and quasar templates in the optical and near infrared, and with a set of dust emission templates (cirrus, M82 starburst, Arp 220 starburst, and AGN dust torus) in the mid infrared.

The optical data, together with the IRAC 3.6 and 4.5 μm data, have been used to determine photometric redshifts. For galaxies with known spectroscopic redshifts there is a notable improvement in the photometric redshift when the IRAC data are used, with a reduction in the rms scatter from 10 % in (1+z) to 5 %. While further spectroscopic data are needed to confirm this result, the prospect of determining good photometric redshifts for the 2 million extragalactic objects in SWIRE is excellent. The distribution of the different infrared sed types in the Lir/Lopt versus Lir plane, where Lir and Lopt are the infrared and optical bolometric luminosities, is discussed. Source-counts at 24, 70 and 160 μm are discussed, and luminosity functions at 3.6 and 24 μm are presented.

Back to Volume