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Astron. Astrophys. 360, 1-9 (2000)

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Implications of the cosmic infrared background for light production and the star formation history in the Universe *

R. Gispert  ** , G. Lagache and J.L. Puget

Université Paris XI, Institut d'Astrophysique Spatiale, Bâtiment 121, 91405 Orsay Cedex, France

Received 24 November 1999 / Accepted 16 May 2000


The Cosmic Background due to the integrated radiation from galaxies over the whole life of the Universe is reviewed. We find that this background is well constrained by measurements. The total power in the background is in the range 60-93 nWm-2sr-1. The data show the existence of a minimum separating the direct stellar radiation from the infrared part due to radiation reemitted by dust. This reemitted dust radiation is about 1-2.6 time the background power in the optical/near-IR thus much larger than the same ratio measured locally ([FORMULA]). The far-infrared and submillimeter background is likely to be dominated by redshifted infrared galaxies. The long wavelength spectrum of the background being significantly flatter than the spectrum of these galaxies it strongly constrains the far-infrared radiation production rate history which must increase by a factor larger than 10 between the present time and a redshift 1 and then stays rather constant at higher redshift, contrary to the ultraviolet radiation production rate which decreases rapidly.

Several models of galaxy evolution have been proposed to explain the submillimeter background. In this paper we do not propose a new model; we systematically explore the allowed range of evolution histories allowed by the data. If infrared galaxies are mostly powered by starbursts as indicated by recent observations, this infrared production history reflects the history of starformation in the Universe.

Key words: cosmology: observations – cosmology: diffuse radiation – infrared: galaxies

* Appendix 1 and 2 are only available electronically here in the On-Line version
** Richard Gispert died in the final stages of the preparation of this paper in August 1999.

Send offprint requests to: G. Lagache (lagache@ias.fr)

© European Southern Observatory (ESO) 2000

Online publication: July 27, 2000