The SMA ~100pc view of CO (2-1)/(1-0) in M51

Maria Jesus Jimenez-Donaire

Thursday December 4th, 09:35

Our most accessible CO line ratio, (2-1)/(1-0), remains poorly understood in the extragalactic, high-resolution context: we lack a good prescription for how it varies across galaxies and its diagnostic power remains under-developed. I will present the first results from our large Submillimeter Array (SMA) program to map the inner 10x6kpc of our best-studied galaxy, M51, in CO(2-1) at ~100pc resolution. In combination with the PdBI program PAWS, this survey provides for the first time a ~100pc-scale map of the CO 2-1/1-0 line ratio across the whole active region of the galaxy. I will discuss quantitative variations of the line ratio across spiral arms and as a function of dynamical environment and star formation activity. Moreover, I will present ongoing follow-ups of the program, including 1” mapping of selected fields, and extended maps to cover the galaxy's companion, M51b.