S2COSMOS: Evolution of gas mass with redshift using dust emission

Abstract

We investigate the evolution of the gas mass fraction for galaxies in the COSMOS field using submillimetre emission from dust at 850µm. We use stacking methodologies on the 850 µm S2COSMOS map to derive the gas mass fraction of galaxies out to high redshifts, 0 ≤ z ≤ 5, for galaxies with stellar masses of 10 9.5 < M * (M ) < 10 11.75 . In comparison to previous literature studies we extend to higher redshifts, include more normal star-forming galaxies (on the main sequence), and also investigate the evolution of the gas mass fraction split by star-forming and passive galaxy populations. We find our stacking results broadly agree with scaling relations in the literature. We find tentative evidence for a peak in the gas mass fraction of galaxies at around z ∼ 2.5 − 3, just before the peak of the star formation history of the Universe. We find that passive galaxies are particularly devoid of gas, compared to the star-forming population. We find that even at high redshifts, high stellar mass galaxies still contain significant amounts of gas.

VALES VI: ISM enrichment in star-forming galaxies up to z ∼ 0.2 using 12CO(1–0), 13CO(1–0), and C18O(1–0) line luminosity ratios

“…An independent approach has been the development of stacking techniques. This has been successful to detect the combined signal of faint emission coming from multiple objects of the same population over the electromagnetic spectrum, including the X-ray (Bartelmann & White 2003;Rodighiero et al 2015;Yang et al 2018), UV (Berry et al 2012;Rigby et al 2018), infrared (Dole, et al 2006;Duivenvoorden et al 2020), submm (Webb et al 2003;Knudsen et al 2005;Ibar et al 2013;Millard et al 2020), and radio (Miller et al 2013;Bera et al 2018;Perger et al 2019) regimes. Moreover, stacking techniques have proven to be a robust method for line and continuum detections of high redshift galaxies (Scoville et al 2007;Lehmer et al 2007;Schinnerer et al 2007;Miller et al 2008).…”

IllustrisTNG and S2COSMOS: possible conflicts in the evolution of neutral gas and dust

“…Here, we will briefly summarize the observational data used to derive average dust properties of physical galaxies over cosmic time, and also describe the simulations from IllustrisTNG used in this study. The observational data sets and catalogues used to compare with the simulations are described in more detail in Millard et al (2020).…”

“…We derive the dust masses of galaxies in the S2COSMOS field by stacking on the 850 μm map (Millard et al 2020). As such, we require a source catalogue to provide the locations of COSMOS galaxies, which we briefly discuss in the next section.…”

“…Furthermore, since cosmic dust is an important constituent of the ISM and pervasive throughout it, dust has been found to be useful as a tracer to estimate the molecular gas content of galaxies, the fuel for future star formation. The optically thin dust continuum emission detected at a single sub-mm wavelength can be used as a tracer of molecular gas (Eales et al 2012;Scoville et al 2014Scoville et al , 2016Scoville et al , 2017Tacconi et al 2018;Millard et al 2020).…”

“…Despite several studies illustrating the usefulness of sub-mm dust emission as a tracer for gas mass (e.g. Béthermin et al 2015;Genzel et al 2015;Scoville et al 2016Scoville et al , 2017Tacconi et al 2018;Millard et al 2020), such calculations involve significant assumptions. For example, the studies implicitly assume that metallicity does not evolve with redshift and that the fraction of metals incorporated in dust grains is a constant, or equivalently that the dust-to-gas ratio is constant with time.…”