Our First "Cloud-Scale" Survey of Molecular Gas, Dust, and Star Formation in Galaxies

I will present "PHANGS-ALMA" a multi-cycle survey of 90 nearby galaxies using the Atacama Large submillimeter/Millimeter Array (ALMA) that offered our first real "cloud scale" survey of molecular gas in galaxies. Stars form in giant molecular clouds, which are dense, cold condensations of gas that in many ways act as the engines of galaxy evolution. The demographics, evolution, and physical state of these clouds relate directly to how star formation proceeds, feedback operates, and galaxies grow. Until recently, however, we lacked any large survey that resolved the gas in galaxies into individual clouds. Leveraging ALMA's amazing combination of resolution, sensitivity, and mapping speed, PHANGS-ALMA mapped the CO 2-1 emission, our basic tracer of molecular gas in galaxies, at 1" = 50-150 pc resolution scales across essentially all accessible very nearby star-forming galaxies. On its own, PHANGS-ALMA resolves the molecular gas across whole galaxies into individual star-forming molecular clouds, giving access to the demographics and properties of tens of thousands of molecular clouds across a representative set of z=0 galaxies. When paired with our large programs on VLT/MUSE, the Hubble Space Telescope, ALMA mapping of high critical density lines, and now JWST and MeerKAT, PHANGS offers a pan-chromatic view that breaks a representative sample of galaxies into individual star forming regions for the first time. I will give an overview of the motivation and execution of the survey, describe the data and products available to the community, and then highlight results on a few key topics - demographics, life cycles, and star formation properties of clouds - from the PHANGS team and discuss some of the first results from pairing ALMA and JWST to study the interstellar medium and star formation in galaxies.