The evolution of the dust and gas content in galaxies
Abstract
We use deep Herschel PACS and SPIRE observations in GOODSS, GOODSN and COSMOS to estimate the average dust mass (Mdust) of galaxies on a redshift-stellar mass (Mstar)-SFR grid. We study the scaling relations between Mdust, Mstar and SFR at z<=2.5. No clear evolution of Mdust is observed at fixed SFR and Mstar. We find a tight correlation between SFR and Mdust, likely a consequence of the Schmidt-Kennicutt (S-K) law. The Mstar-Mdust correlation observed by previous works flattens or sometimes disappears when fixing the SFR. Most of it likely derives from the combination of the Mdust-SFR and Mstar-SFR correlations. We then investigate the gas content as inferred by converting Mdust by assuming that the dust/gas ratio scales linearly with the gas metallicity. All galaxies in the sample follow, within uncertainties, the same SFR-Mgas relation (integrated S-K law), which broadly agrees with CO-based results for the bulk of the population, despite the completely different approaches. The majority of galaxies at z~2 form stars with an efficiency (SFE=SFR/Mgas) ~5 times higher than at z~0. It is not clear what fraction of such variation is an intrinsic redshift evolution and what fraction arises from selection effects. The gas fraction (fgas) decreases with Mstar and increases with SFR, and does not evolve with z at fixed Mstar and SFR. We explain these trends by introducing a universal relation between fgas, Mstar and SFR, non-evolving out to z~2.5. Galaxies move across this relation as their gas content evolves in time. We use the 3D fundamental fgas-Mstar-SFR relation and the redshift evolution of the Main Sequence to estimate the evolution of fgas in the average population of galaxies as a function of z and Mstar, and we find evidence a downsizing scenario.
Keywords
Cite
@article{arxiv.1311.3670,
title = {The evolution of the dust and gas content in galaxies},
author = {P. Santini and R. Maiolino and B. Magnelli and D. Lutz and A. Lamastra and G. Li Causi and S. Eales and P. Andreani and S. Berta and V. Buat and A. Cooray and G. Cresci and E. Daddi and D. Farrah and A. Fontana and A. Franceschini and R. Genzel and G. Granato and A. Grazian and E. Le Floc'h and G. Magdis and M. Magliocchetti and F. Mannucci and N. Menci and R. Nordon and S. Oliver and P. Popesso and F. Pozzi and L. Riguccini and G. Rodighiero and D. J. Rosario and M. Salvato and D. Scott and L. Silva and L. Tacconi and M. Viero and L. Wang and S. Wuyts and K. Xu},
journal= {arXiv preprint arXiv:1311.3670},
year = {2015}
}
Comments
Accepted for publication in A&A