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Institute for the Physics and Mathematics of the UniverseWPI

Structure Formation in the Early Universe

Dates: Jan 9, 4 pm, Main Seminar Room, 6th floor, ICRR Kashiwa Campus of the University of Tokyo
Speaker: Naoki Yoshida (Department of Physics, Nagoya University)
Title: Structure Formation in the Early Universe - Dark Ages, First Light, and Dark Matter -
Abstract: Primordial stars are thought to be formed from a chemically pristine gas
consisting of hydrogen and helium. They are believed to have been born
at some early epoch in the history of the universe. They are the sources
of first light, and an origin of heavy elements which we ourselves
consist of.
I use ultra high-resolution supercomputer simulations of early structure
formation in the standard Cold Dark Matter cosmogony.
Our approach includes all the relevant atomic and molecular processes,
in addition to gravity and hydrodynamics, to follow the thermal and
evolution of a primordial gas. Our simulation achieves a dynamic
range of 1012 in length scale, and follow prestellar gas collapse
over 20
decades in density without assuming any a priori equation of state;
an improvement of 10 orders of magnitudes(!) over previous studies.
I will show details of the formation process of primordial stars.
I discuss implications for cosmic reionization.
Particle properties of dark matter significantly affect the structure
in the early universe. The shape of the initial density perturbation
(i.e., inflaton potential) and the nature of dark energy are
important, too.
I discuss prospects for future observations in from radio to gamma-rays.