Program: GS-2023A-Q-703

Title:Constraints on the quenching mechanism of the most massive, passive red disk galaxies at z~1.5
PI:Bomee Lee
Co-I(s): Andreas Faisst

Abstract

The population-averaged star formation of galaxies drops significantly after z=2 due to quenching of star formation, which mechanisms are currently still not fully understood. Massive and passive red disk galaxies, found at low and high redshifts, are especially curious cases as they cannot be explained by most common quenching mechanisms. We propose to carry out a detailed spectroscopic study of the 5 most massive and passive disk galaxies at z=1.5 on the COSMOS field using GNIRS. Specifically, we will (i) verify their quiescent by measuring strong optical emission lines, (ii) pinpoint their stellar population ages via the measurement of optical absorption lines and Dn4000, and (iii) search for AGN signatures. These observations will allow us to understand how and when these galaxies were quenched, thus putting important constraints on the formation of such massive passive disk galaxies and quenching models at these redshifts. In addition, secure redshifts lay the foundation for studying the cold gas reservoir of these galaxies in detail in the future with sub-mm facilities such as ALMA.