Redshift evolution of stellar mass versus gas fraction relation in 0<z<2 regime: observational constraint for galaxy formation models

Original · EN

We investigate the redshift evolution of the molecular gas mass fraction (fₘol=Mₘol/(Mₛtar+Mₘol), where Mₘol is molecular gas mass and Mₛtar is stellar mass) of galaxies in the redshift range of 0<z<2 as a function of the stellar mass by combining CO literature data. We observe a stellar-mass dependence of the fₘol evolution where massive galaxies have largely depleted their molecular gas at z=1, whereas the fₘol value of less massive galaxies drastically decreases from z=1. We compare the observed Mₛtar-fₘol relation with theoretical predictions from cosmological hydrodynamic simulations and semi-analytical models for galaxy formation. Although the theoretical studies approximately reproduce the observed mass dependence of fₘol evolution, they tend to underestimate the fₘol values, particularly of less massive (<10¹0 Msun) and massive galaxies (>10¹1 Msun) when compared with the observational values. Our result suggests the importance of the feedback models which suppress the star formation while simultaneously preserving the molecular gas in order to reproduce the observed Mₛtar-fₘol relation.