The Interstellar Medium

$Atomic and molecular gas across the local galaxy population. In each panel, the galaxies of the xCOLDGASS survey (Saintonge et al., 2017) are shown in comparison to the full galaxy population at low redshift (SDSS; gray countours), and color-coded by a specific ISM-related parameter (black dots are non-detections in the Hi and/or CO emission lines). The quantities shown are the atomic gas mass fraction (fHI≡MHI/M∗; left), the molecular gas mass fraction (fH2≡MH2 /M∗; middle), and the molecular gas depletion timescale (tdep(H2)≡MH2 /SFR; right). The solid and dashed lines shows the position and width of the main sequence. Figure reproduced from Saintonge and Catinella (2022). -- astro-ph.GA$

The interstellar medium (ISM) is the material that fills the space between the stars in all galaxies; it is a multi-phase medium in pressure equilibrium, with densities and temperatures covering … Continue reading The Interstellar Medium