A 50 pc scale view of star formation efficiency across NGC 628
  Star formation is a multi-scale process that requires tracing cloud formation
and stellar feedback within the local (<kpc) and global galaxy environment. We
present first results from two large observing programs on ALMA and VLT/MUSE,
mapping cloud scales (1arcsec = 47pc) in both molecular gas and star forming
tracers across 90 kpc^2 of the central disk of NGC 628 to probe the physics of
star formation. Systematic spatial offsets between molecular clouds and HII
regions illustrate the time evolution of star-forming regions. Using uniform
sampling of both maps on 50-500 pc scales, we infer molecular gas depletion
times of 1-3 Gyr, but also find the increase of scatter in the star formation
relation on small scales is consistent with gas and HII regions being only
weakly correlated at the cloud (50 pc) scale. This implies a short overlap
phase for molecular clouds and HII regions, which we test by directly matching
our catalog of 1502 HII regions and 738 GMCs. We uncover only 74 objects in the
overlap phase, and we find depletion times >1 Gyr, significantly longer than
previously reported for individual star-forming clouds in the Milky Way.
Finally, we find no clear trends that relate variations in the depletion time
observed on 500 pc scales to physical drivers (metallicity, molecular and
stellar mass surface density, molecular gas boundedness) on 50 pc scales.
