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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, Naoyuki Tamura) by email : (please change"_at" to @).

September 30, Tuesday at 11:00 am

" The ACS LCID project: accurate measurements of the full star formation history in low metallicity, isolated, Local Group dwarf galaxies "

Matteo Monelli (Instituto de Astrofisica de Canarias)

The star formation history of Local Group galaxies is a powerful tool for studying their evolution, including chemical enrichment histories and stellar population gradients, which in turn may shed light on the role of reionization or Supernovae feedback in dwarf galaxy formation and evolution. In particular, isolated dwarfs are ideal laboratories since their evolution has not been complicated by the vicinity of giant galaxies. We will discuss the main results of the project Local Cosmology from Isolated Dwarfs (LCID), aimed at deriving detailed star formation histories for a sample of six Local Group isolated dwarf, low metallicity, galaxies: two dIrr (IC1613 and Leo A), two transition dIrr/dSph (LGS3 and Phoenix) and the only two isolated dSph in the Local Group (Cetus and Tucana). To accomplish this goal we have collected, using the ACS on board the HST, color-magnitude diagrams reaching their oldest main sequence turnoff (V~28) with good photometric accuracy. Accurate star formation histories have been derived through comparison with synthetic color-magnitude diagrams, using the IAC-pop algorithm. All galaxies in our sample, except Leo A, show a substantial amount of old stellar population, even though the subsequent evolution is varied. We will discuss the implications of these star formation histories on current scenarios of dwarf galaxy formation and evolution.

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

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