The CO-H2 Conversion Factor in Galaxy Mergers
  The CO-H2 conversion factor in galaxies is typically described as bimodal: one value for discs and quiescent regions, and another (lower) value for mergers and starbursts. In this proceeding, I will describe both empirical observational evidence that the conversion factor varies with physical environment, as well as a theoretical model which aims to understand the physical processes which drive these variations. I present a functional form for Xco which can be applied to observations ranging in scale from ~70 pc to galaxy-wide scales, and show the consequences of the application of this model to the Kennicutt-Schmidt star formation law. 
Desika Narayanan (University of Arizona)
astro-ph.CO