Program: GN-2019A-Q-234

Title:The Morphological Transformation as Revealed by Age Gradients and Rotational Support in Post-starburst Galaxies at z~0.6
PI:Rachel Bezanson
Co-I(s): Justin Spilker, David Setton, Katherine Suess, Mariska Kriek, Jenny Greene, Qiana Hunt

Abstract

In the last decade observations have revealed that quiesent galaxies were much more compact at earlier epochs. Several mechanisms have been proposed to quench star formation and form these extremely dense spheroids including: (1) compaction via violent disk instabilities or minor merging, (2) gas-rich major mergers, and (3) dissipational collapse formation. Each mechanism would leave characteristic marks on the distribution and motion of stars. However these signatures will disappear with time, age indicators are most sensitive for ~1 Gyr and minor merging will smooth age gradients and diminish rotation. We propose to test these formation models in post-starburst galaxies, which represent the direct, unpolluted products of the quenching process. Although they are extremely rare below z~1, we have leveraged the wide-area of the SDSS spectroscopic survey to identify post-starburst galaxies during the epoch of their decline. Using the GMOS IFU spectrographs we propose to measure spatially resolved stellar populations and kinematics from stellar absorption features for two of the brightest post-starburst galaxies. This proposal builds on successful Gemini FT and 2017A/2017B/2018B programs and two completed ALMA programs quantifying the surprising molecular gas reservoirs of these unique objects. The proposed observations would complete the full sample of 10 galaxies with GMOS and ALMA data. With the combined dataset we will constrain the physical mechanisms responsible for forming massive quiescent galaxies.

Publications using this program's data