The selective effect of environment on the atomic and molecular gas-to-dust ratio of nearby galaxies in the Herschel Reference Survey

• Published in: Monthly notices of the Royal Astronomical Society Vol. 459; no. 4; pp. 3574 - 3584
• Main Authors: Cortese, L., Bekki, K., Boselli, A., Catinella, B., Ciesla, L., Hughes, T. M., Baes, M., Bendo, G. J., Boquien, M., de Looze, I., Smith, M. W. L., Spinoglio, L., Viaene, S.
• Format: Journal Article
• Language: English
• Published: London Oxford University Press 11.07.2016; Oxford University Press (OUP): Policy P - Oxford Open Option A
• Subjects: Accretion disks; Astrophysics; Comparative analysis; Cosmic dust; Dust; Galaxies; Hydrogen; Interstellar matter; Mathematical models; Metallicity; Phases; Sciences of the Universe; Star & galaxy formation; galaxies: fundamental parameters; intergalactic medium; galaxies: clusters: general; galaxies: evolution
• ISSN: 0035-8711; 1365-2966
• DOI: 10.1093/mnras/stw801

We combine dust, atomic (H i) and molecular (H2) hydrogen mass measurements for 176 galaxies in the Herschel Reference Survey to investigate the effect of environment on the gas-to-dust mass (M gas/M dust) ratio of nearby galaxies. We find that, at fixed stellar mass, the average M gas/M dust ratio varies by no more than a factor of ∼2 when moving from field to cluster galaxies, with Virgo galaxies being slightly more dust rich (per unit of gas) than isolated systems. Remarkably, once the molecular and atomic hydrogen phases are investigated separately, we find that H i-deficient galaxies have at the same time lower $M_{\rm H\,\small {I}}/M_{\rm dust}$ ratio but higher $M_{\rm H_{2}}/M_{\rm dust}$ ratio than H i-normal systems. In other words, they are poorer in atomic but richer in molecular hydrogen if normalized to their dust content. By comparing our findings with the predictions of theoretical models, we show that the opposite behaviour observed in the $M_{\rm H\,\small {I}}/M_{\rm dust}$ and $M_{\rm H_{2}}/M_{\rm dust}$ ratios is fully consistent with outside-in stripping of the interstellar medium (ISM), and is simply a consequence of the different distribution of dust, H i and H2 across the disc. Our results demonstrate that the small environmental variations in the total M gas/M dust ratio, as well as in the gas-phase metallicity, do not automatically imply that environmental mechanisms are not able to affect the dust and metal content of the ISM in galaxies.