Models for infrared and submillimetre counts and backgrounds
Abstract
Description
A simple and versatile parameterized approach to the star formation history allows a quantitative investigation of the constraints from far infrared and submillimetre counts and background intensity measurements.
The models include four spectral components: infrared cirrus, an M82-like starburst, an Arp220-like starburst and an AGN dust torus. The 60 $μ$m luminosity function is determined for each chosen rate of evolution using the PSCz redshift data for 15000 galaxies. The proportions of each spectral type as a function of 60 $μ$m luminosity are chosen for consistency with IRAS and SCUBA colour-luminosity relations, and with the fraction of AGN as a function of luminosity found in 12 $μ$m samples.
A good fit to the observed counts at 0.44, 2.2, 15, 60, 90, 175 and 850 $μ$m can be found with pure luminosity evolution in all 3 cosmological models investigated: $Ω_o$ = 1, $Ω_o$ = 0.3 ($Λ$ = 0), and $Ω_o$ = 0.3, $Λ$ = 0.7. All 3 models also give an acceptable fit to the integrated background spectrum. The total mass-density of stars generated is consistent with that observed, in all 3 cosmological models.
15 pages, 11 figs. to appear in 'The Extragalactic Infrared Background and its Cosmological Implications', IAU Symposium 204, eds M.Harwit and M.G.Hauser
15 pages, 11 figs. to appear in 'The Extragalactic Infrared Background and its Cosmological Implications', IAU Symposium 204, eds M.Harwit and M.G.Hauser