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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.


Seminars are also held at JAC, CFHT, and IfA.



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