How it started . . . How it’s going: Tracing the formation and evolution of massive galaxies through cosmic time 

Galaxies are extraordinarily complex collections of stars, gas, and dark matter. The largest galaxies, though relatively rare in number, host most of the stars in the Universe and deep in their cores harbor the most extreme supermassive black holes. Today massive galaxies are red and dead ellipticals with little ongoing star formation or organized rotation; naturally they were expected to be relics of a much earlier formation epoch. In this talk I will briefly review the paradigm that has emerged over the last decade, discussing the structural and kinematic evolution of massive galaxies during and after they stopped forming stars (“quenched”) and eventually transformed from rotationally supported disks into kinematically hot ellipticals. Spectroscopic studies of distant galaxies reveal the chemical compositions, detailed star formation histories, and internal motions of stars and gas and are necessary to answer open questions about the details of that cosmic formation and shutdown. I will describe my team’s observational efforts to characterize the histories of galaxies like our Milky Way and larger at three critical moments in the 14 billion year history of the Universe, each corresponding to a large spectroscopic program.  This work includes studying galaxy metamorphosis at ~half the age of the Universe, highlighting results from the ultra-deep LEGA-C spectroscopic survey of ~3500 massive galaxies and the focused multi-wavelength SQUIGGLE survey of post-starburst galaxies caught immediately following their cosmic shutdown. I will discuss our plans to extend spectroscopic studies of galaxies to the earliest moments in cosmic history, with the UNCOVER treasury program on the upcoming NASA flagship observatory - JWST. Finally, my team will connect-the-dots through the peak of cosmic star formation (~10 billion years ago) using the next-generation massively multiplexed Prime Focus Spectrograph on the Subaru Telescope.