Extremely Low Molecular Gas Content in a Compact, Quiescent Galaxy at z=1.522

Understand

One of the greatest challenges to theoretical models of massive galaxy formation is the regulation of star formation at early times.

• The relative roles of molecular gas expulsion, depletion, and stabilization are uncertain as direct observational constraints of the gas reservoirs in quenched or quenching galaxies at high redshift are scant.
• We present ALMA observations of CO(2-1) in a massive ($\log M_{\star}/M_{\odot}=11.2$), recently quenched galaxy at $z=1.522$.
• The optical spectrum of this object shows strong Balmer absorption lines, which implies that star formation ceased $\sim$0.8 Gyr ago.