Panchromatic Hubble Andromeda Treasury (PHAT)

The Panchromatic Hubble Andromeda Treasury (PHAT) is a Hubble Space Telescope (HST) survey of the disk of the Andromeda Galaxy, the closest large galaxy to the Milky Way.  With over 40 full days of HST time, PHAT measure the luminosities and colors of nearly 120 million individual stars over 1/3 of Andromeda's star-forming disk.  PHAT is one of the largest and most ambitious Hubble programs in history, and has led to new insights into a wide variety of galaxy and stellar astrophysics from the evolution of the Andromeda galaxy across comic time to the intricate details of star-formation and its interplay with Andromeda gas supply.