CCA Colloquium: Evan Kirby

Title: First Observations from the PFS Galactic Archaeology Survey

Abstract: The Subaru Prime Focus Spectrograph is a new wide-field, massively multiplexed spectrograph at the prime focus of the Subaru 8 m telescope.  In March 2025, it began a 360-night survey spread over six years.  About one third of the survey is dedicated to Galactic Archaeology: (1) dark matter and chemical abundances of seven nearby dwarf galaxies, (2) the assembly history of M31 as seen through alpha element abundances, and (3) the history of minor mergers in the Milky Way as seen through the chemistry and dynamics of the most fragile parts of the Galaxy: the halo and outer disk.

The first targets for the survey were the Milky Way satellite galaxies Draco and Ursa Minor.  I will present preliminary measurements of chemical abundance distributions of these two dwarf spheroidal galaxies.  I will discuss the performance of the instrument and its software pipelines.  I will also preview the next five and a half years of the PFS Galactic Archaeology survey.

September 5, 2025