***********************************************************
OATS-DAUT SEMINAR
***********************************************************

Speaker: Kentaro Nagamine (Univ. of California, San Diego, USA)

Title: The History of Cosmological Star Formation: Three Independent Approaches and a Critical Test Using the Extragalactic Background Light

***********************************************************
Abstract:
Taking three independent approaches, I will discuss the evolution of stellar mass and star formation rate (SFR) in the context of hierarchical structure formation based on the concordance Lambda cold dark matter model. We compare results based on: 1) direct observations of past light-cone, 2) a model using local fossil evidence constrained by SDSS observations at z~0 (the `Fossil' model), and 3) theoretical ab initio models from three calculations of cosmic star formation history. We find good agreement among the three independent approaches up to the order of observational errors, except that all the models predict bolometric EBL of I_EBL ~= 40-55 nW m^-2 sr^-1, which is at the lower edge of the the observational estimate by Hauser & Dwek. We emphasize that the Fossil model that consists of two components -- spheroids and disks --, when normalized to the local observations, provides a surprisingly simple but accurate description of the cosmic star formation history and other observable quantities. It shows an essentially constant star formation rate from z=7 to z=2. Linking the spheroids and bulges, I will also refer to the black hole formation rate and the associated X-ray background light.
***********************************************************