November 18, 1999 CfA Colloquium


Title: The First Detections of the Extragalactic Background Light at 3000, 5500, and 8000Å

Speaker: Rebecca Bernstein

Abstract: The integrated optical surface brightness of the Universe --- the optical extragalactic background light --- is dominated by starlight from resolved and unresolved sources out to redshifts z<8. As such, it is a fundamental constraint on the star formation history of the Universe. In this talk, I will discuss the first measurements of the mean flux of the optical EBL at 3000, 5500, and 8000Å and the coordinated HST/ground--based observing program from which these results were obtained. The EBL flux we detect is significantly larger than the integrated flux of resolved galaxies measured with standard photometric methods. Based on these results, we can quantify the fraction of the EBL which comes from resolved galaxies and estimate the flux which is expected to arise from unresolvable, high redshift galaxies assuming simple passive evolution of local galaxy populations. Finally, I will discuss the implications of these results in the context of infrared EBL measurements and complementary estimates of the star formation history, metal enrichment, and stellar baryon fraction of the Universe.

Student Lunch: Thursday 11/18 at 12:00 in A-101

Further Reading: