Jakob den Brok (Harvard CfA)
Unraveling the molecular gas conditions across nearby galaxies – new insights from recent large mm line programs.
An intricate interplay exists between the molecular gas in the interstellar medium (ISM) and the onset of star formation. Gaining insight into the molecular gas's composition and its physical and chemical conditions is crucial to comprehending how star formation is regulated, and how galaxies evolve. However, the most abundant molecule, H_2, is challenging to observe directly under commonly cold ISM conditions across nearby galaxies. Carbon Monoxide (CO) emission has become the most accessible tracer of the bulk molecular ISM distribution. I will present recent findings from CO and isotopologue line emission surveys in nearby galaxies. With these, I explore the CO excitation conditions from kiloparsec to 100s-parsec scales. Using deep low rotational-J 13CO, C18O, and C17O transition observations, it is possible to assess the chemical enrichment of C and O. Furthermore, I present the analysis of variations in the CO-to-H_2 conversion factor, which is needed accurately translate the observed CO brightness into a H_2 mass surface density. I link these variations to different galactic environments across the entire molecular disk of the star-forming galaxies M51 and M101. In summary, my talk illustrates the use of CO line observations as diagnostics for accurately accounting and interpreting the variation of CO-derived properties of the molecular ISM from kiloparsec to 100s-parsec scales.
In person at PRB 4138 (the “cliffhanger room”)
Virtual on Zoom (https://osu.zoom.us/j/98260642016?pwd=cW9yNDJVNU11Z1FIekVXaVVPTEF1Zz09)
