Massive Dead Galaxies at z~2 with HST Grism Spectroscopy I. Star Formation Histories and Metallicity Enrichment

Understand

Observations have revealed massive (logM*/Msun>11) galaxies that were already dead when the universe was only ~2 Gyr.

• Given the short time before these galaxies were quenched, their past histories and quenching mechanism(s) are of particular interest.
• In this paper, we study star formation histories (SFHs) of 24 massive galaxies at 1.6<z<2.5.
• A deep slitless spectroscopy + imaging data set collected from multiple Hubble Space Telescope surveys allows robust determination of their spectral energy distributions and SFHs with no functional assumption on their forms.