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Paper: The Spitzer View of Galaxy Evolution
Volume: 379, Cosmic Frontiers
Page: 151
Authors: Rowan-Robinson, M.
Abstract: I discuss the impact of SPITZER on our understanding of galaxy evolution. Significant numbers of z ~ 6 have already been found with IRAC and there have been a number of surveys of different classes of star-forming galaxies at z = 2-3. In the largest of the SPITZER Legacy Surveys, SWIRE, covering 49 sq deg, over a million galaxies have been found. 10% of these are estimated to be at z > 2, and 4 % at z > 3.

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. 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 4%. 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 compared with a new model, and luminosity functions at 3.6 and 24 μm are presented. The clustering of SWIRE galaxies at z ~ 2 -3 is discussed.

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