THE EVOLUTION OF INTERSTELLAR MEDIUM MASS PROBED BY DUST EMISSION: ALMA OBSERVATIONS AT z= 0.3-2

Abstract

The use of submillimeter dust continuum emission to probe the mass of interstellar dust and gas in galaxies is empirically calibrated using samples of local star-forming galaxies, Planck observations of the Milky Way, and high-redshift submillimeter galaxies. All of these objects suggest a similar calibration, strongly supporting the view that the Rayleigh–Jeans tail of the dust emission can be used as an accurate and very fast probe of the interstellar medium (ISM) in galaxies. We present ALMA Cycle 0 observations of the Band 7 (350 GHz) dust emission in 107 galaxies from z = 0.2 to 2.5. Three samples of galaxies with a total of 101 galaxies were stellar-mass-selected from COSMOS to have M * ≃ 10 11 M ☉ : 37 at z ∼ 0.4, 33 at z ∼ 0.9, and 31 at z = 2. A fourth sample with six infrared-luminous galaxies at z = 2 was observed for comparison with the purely mass-selected samples. From the fluxes detected in the stacked images for each sample, we find that the ISM content has decreased by a factor ∼6 from 1 to 2 × 10 10 M ☉ at both z = 2 and 0.9 down to ∼2 × 10 9 M ☉ at z = 0.4. The infrared-luminous sample at z = 2 shows a further ∼4 times increase in M ISM compared with the equivalent non-infrared-bright sample at the same redshift. The gas mass fractions are ∼2% ± 0.5%, 12% ± 3%, 14% ± 2%, and 53% ± 3% for the four subsamples ( z = 0.4, 0.9, and 2 and infrared-bright galaxies).