2025-05-29 –, Main Conference Room
I will present a series of recent results from ALMA and IRAM campaigns targeting -in particular density-sensitive- molecular line ensembles like HCN, HCO+, HNC, CS or N2H+ and low-J CO, but also a range of faint CO isotopologues like 13CO or C18O across and among nearby spiral galaxies. The data situation of resolved "mm-spectroscopy" across nearby galaxies has improved dramatically over the last ~10 years and significant progress was made probing canonical, extragalactic, density-sensitive line ratios like HCN/CO or HCO+/CO and their relation with star formation in diverse samples of around 30 nearby galaxies. I will introduce a comprehensive kpc-scale ALMA ACA survey (ALMOND), targeted higher-resolution ALMA follow-up and the NOEMA Large Program SWAN, mapping these molecular lines directly at cloud scales across M51. In this talk, I will synthesize the key results from these campaigns and what they tell us about dense gas fractions and star formation efficiencies from larger scales to cloud scales across local galaxies, how the various canonical extragalactic tracers compare and outline intriguing links to cloud-scale work in the Milky Way.
