As the nearest metal-rich, star-forming galaxy to the Milky Way, M31 plays a key role in understanding the interstellar medium (ISM) and star formation at z~0. Because of its proximity, we can study the properties of the ISM on the scale of individual star-forming molecular clouds and characterize the stellar sources of energy input for the ISM gas and dust. Recent observations have emphasized the importance cloud-scale processes in setting the efficiency of star formation. In particular, the formation of bound molecular clouds out of the cold neutral medium is a critical step in the process. Small spatial scale processes are also crucial for generating the tracers of star formation we use to study distant galaxies. M31 is currently the only metal-rich galaxy where existing observational facilities let us probe these important scales in all of the relevant tracers. Towards that end, we have assembled a powerful multi-wavelength observational dataset for a large portion of the disk of M31 – including HI 21-cm and radio continuum mapping from the VLA, CO J=(1-0) mapping from CARMA, Spitzer and Herschel photometry, Herschel spectroscopy, optical integral field spectroscopy, and resolved stellar photometry from the Pan-chromatic Hubble Andromeda Treasury (PHAT). I will summarize what we have learned about the connection between star formation and the ISM from this unique dataset.
NOTE: Refreshments at 3:45pm; talk begins at 4:00pm.