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The Subaru Seminar is
usually held in Room 104 of the Hilo Base Facility, adjacent
to the main lobby. Everyone is welcome to attend. If you are
interested in giving a seminar, please contact Subaru
seminar organizers (Tomonori Usuda, Kumiko S. Usuda, Masahiko Hayashi, Masayuki Akiyama)
by email.
January 13, Friday at 11:00am
" Simulating the formation and evolution of galaxies;
Chiaki Kobayashi
(Division of Theoretical Astronomy, NAOJ)
While the evolution of dark matter structure in the standard Lambda-
CDM cosmology is reasonably well understood, the evolution of the
baryon component is less certain because of the complexity of
physical processes such as star formation and feedback. We simulate
cosmic chemical evolution with a N-body SPH code in which we include
star formation, supernova and hypernova feedback, and chemical
enrichment.
For assumptions which produce plausible results in idealised collapse
models of individual galaxies, the cosmic star formation rate shows a
peak at z~4, and ~10% of baryon turn to stars. Stars in present-day
massive galaxies formed in smaller galaxies at high redshifts, giving
an old stellar age consistent with observations.
Galactic winds blow effectively from less massive galaxies and eject
heavy elements into the intergalactic medium, of which process
produces the mass-metallicity relation of galaxies. Metal-enrichment
history depends on the environment, and is consistent with the
observed abundances of Lyman break galaxies, of damped Lyman-alpha
systems, and of the intergalactic medium.
I would like to discuss what kind of observations are required to
investigate the formation and evolution of galaxies with numerical
simulations.