The dust and cold gas content of local star-forming galaxies. Issue 3 (18th June 2020)

• Record Type: Journal Article
• Authors: Popesso, P; Concas, A; Morselli, L; Rodighiero, G; Enia, A; Quai, S
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 496:Issue 3(2020)
• Page Start: 2531
• Page End: 2541
• Publication Date: 2020-06-18
• Subjects: galaxies: evolution -- galaxies: ISM -- galaxies: star formation; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/staa1737
• Languages: English
• ISSNs: 0035-8711

Abstract

ABSTRACT: We use dust masses ( M dust ) derived from far-infrared data and molecular gas masses ( M mol ) based on CO luminosity to calibrate proxies based on a combination of the galaxy Balmer decrement, disc inclination, and gas metallicity. We use such proxies to estimate M dust and M mol in the local SDSS sample of star-forming galaxies (SFGs). We study the distribution of M dust and M mol along and across the main sequence (MS) of SFGs. We find that M dust and M mol increase rapidly along the MS with increasing stellar mass ( M * ), and more marginally across the MS with increasing SFR (or distance from the relation). The dependence on M * is sub-linear for both M dust and M mol . Thus, the fraction of dust ( f dust ) and molecular gas mass ( f mol ) decreases monotonically towards large M * . The star formation efficiency (SFE, inverse of the molecular gas depletion time) depends strongly on the distance from the MS and it is constant along the MS. As nearly all galaxies in the sample are central galaxies, we estimate the dependence of f dust and f gas on the host halo mass and find a tight anticorrelation. As the region where the MS is bending is numerically dominated by massive haloes, we conclude that the bending of the MS is due to a lower availability of molecular gas mass in massive haloes rather than a lower efficiency in forming stars.