The Cosmic Evolution of Molecular Gas Mass Density probed by Dust Emission.
Wednesday
Abstract details
id
The Cosmic Evolution of Molecular Gas Mass Density probed by Dust Emission.
Date Submitted
2019-03-15 14:50:18
Tracy
Garratt
University of Hertfordshire
Studying galaxy evolution from reionization to cosmic noon with the latest-generation multiwavelength facilities
Talk
T. Garratt (Herts), K. Coppin (Herts), J, Geach (Herts)
Three key observational tracers fundamental to our understanding of the cosmic evolution of galaxies are the star formation rate, stellar mass and molecular gas mass. Our current understanding of the cosmic evolution of galaxies is dominated by observations of the former two. Ultimately it is the evolution of the molecular gas mass density which drives the evolution of galaxies because it fuels on-going star formation and is the reservoir from which stars are assembled. In recent years direct measurements have now been placed on the shape of the CO luminosity function, which constrain the evolution of cosmic molecular gas mass density. However, due to low number statistics the statistical uncertainties on these measurements are very large. We use a statistical approach to estimate the evolution of the cosmological molecular gas density, not by measuring the CO luminosity function directly, but by measuring the average observed 850um flux density of a sample ~200,000 galaxies as a function of redshift. We present new empirical constraints on the evolution of the cosmological mass density of molecular hydrogen to z=6, which suggest that the cold molecular gas content in galaxies follows the increase in cosmic star-formation rate towards its peak about 10 billion years ago and declines towards early epochs.
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