Evolution of Cosmic Molecular Gas Mass Density From z ~ 0 to z = 1 -1.5

Fumiya Maeda; Kouji Ohta; Akifumi Seko

doi:10.3847/1538-4357/835/2/120

paper

Evolution of Cosmic Molecular Gas Mass Density From z ~ 0 to z = 1 -1.5

arXiv:1612.04816 · doi:10.3847/1538-4357/835/2/120

Abstract

We try to constrain the cosmic molecular gas mass density at $z = 1 - 1.5$ and that in the local universe by combining stellar mass functions of star-forming galaxies and their average molecular gas mass fractions against the stellar mass. The average molecular gas mass fractions are taken from recent CO observations of star-forming galaxies at the redshifts. The cosmic molecular gas mass density is obtained to be $ρ_{H_{2}} = (6.8 - 8.8) \times 1 0^{7} M_{⊙} Mpc^{- 3}$ at $z = 1 - 1.5$ and $6.7 \times 1 0^{6} M_{⊙} Mpc^{- 3}$ at $z \sim 0$ by integrating down to $0.03 M^{*}$ . Although the values have various uncertainties, the cosmic molecular gas mass density at $z = 1 - 1.5$ is about ten times larger than that in the local universe. The cosmic star formation rate density at $z \sim 1 - 2$ is also about ten times larger than that in the local universe. Our result suggests that the large cosmic molecular gas mass density at $z = 1 - 1.5$ accounts for the large cosmic star formation rate density at $z \sim 1 - 2$ .

arXiv comment6 pages, 2 figures, Accepted for publication in the ApJ

Evolution of Cosmic Molecular Gas Mass Density From z ~ 0 to z = 1 -1.5

Abstract

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