The Cosmic Infrared Background

Presented by Asantha Cooray, University of California, Irvine

In this talk I will summarize the cosmological and astrophysical information content in the cosmic infrared background between 1 to 500 microns. At near-IR wavelengths, the extragalactic background light (EBL) is not yet known to better than a factor of 10 from DIRBE and other absolute photometric measurements due to large uncertainties associated with modeling and removing scattered radiation from zodiacal dust particles in the Solar system. Current estimates of EBL exceed the integrated light associated with galaxies by factor of 5 to 30. I will discuss the Cosmic Infrared Background ExpeRiment (CIBER), a sounding rocket experiment with a payload specifically designed to remeasure the total EBL by establishing the zodiacal contamination in each line-of-sight through a spectrometer tuned to absorption lines in the Solar spectrum. In addition to absolute EBL, spatial fluctuations in the background light in deep images with Spitzer IRAC and HST NICMOS can also be used to search for faint sources that are unresolved individually, including first-light galaxies that are responsible for reionization. I will present recent results from a long-term program that make use of the GOODS and other deep space-based IR data for various fluctuation studies and will present existing limits on the source density at z > 8. Finally, I will summarize cosmological results expected from the wide-field ATLAS survey with Herschel at far-IR wavelengths focusing on the dust-enshrouded star formation.