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OATS-DAUT SEMINAR
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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
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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.
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