2015/11/30 by Floris van der Tak, F. van der Tak, van der Tak, Floris
Physics and Astronomy · #Astrophysics and Star Formation Studies #Astrophysics of Galaxies (astro-ph.GA) #FOS: Physical sciences #Solar and Space Plasma Dynamics #Stellar, planetary, and galactic studies #astro-ph.GA
paper · pdf · doi:10.48550/arxiv.1511.09352
5 pages, 2 figures; to appear in proceedings of IAU focus meeting 15 (Water and organics in the Universe)
arxiv created 2015/11/30 · openalex publication_date 2015/11/30 · arxiv updated 2015/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
This paper reviews recent observations of water in Galactic interstellar clouds and nearby galactic nuclei. Two results are highlighted: (1) Multi-line H2O mapping of the Orion Bar shows that the water chemistry in PDRs is driven by photodissociation and -desorption, unlike in star-forming regions. (2) High-resolution spectra of H2O and its ions toward 5 starburst / AGN systems reveal low ionization rates, unlike as found from higher-excitation lines. We conclude that the chemistry of water strongly depends on radiation environment, and that the ionization rates of interstellar clouds decrease by at least 10 between galactic nuclei and disks.