Astrochemistry and star formation in nearby galaxies: from galaxy disks to hot nuclei

Department of Earth and Space Sciences, Chalmers University of Technology Onsala Space Observatory, 439 92 Onsala, Sweden

Abstract

Studying the molecular phase of the interstellar medium in galaxies is fundamental for the understanding of the onset and evolution of compact and extended star formation, and of the growth of supermassive black holes. Molecular line emission is an excellent tracer of chemical, physical and dynamical conditions in the cold neutral gas. Key molecules in extragalactic studies are e.g. HCN, HCO⁺, HC₃N, SiO, CH₃OH, H₂O. Furthermore, we can use IR excited molecular emission to probe the very inner regions of luminous infrared galaxies allowing us to get past the optically thick dust barrier of the compact obscured nuclei where lines of CO, HCN and HCO⁺ in their vibrational ground state (ν=0) may be self-absorbed. Finally, molecular outflows and their chemistry are briefly discussed – including new ALMA results on for example the outflow of the lenticular galaxy NGC1377 and a study of the chemistry of the outflow of the quasar Mrk231.