Astronomy Colloquium - Rachel Bezanson

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Very Large Telescope (VLT) used in the LEGA-C Survey
November 21, 2019
4:00PM - 5:00PM
Location
E0040 Scott Laboratory

Date Range
Add to Calendar 2019-11-21 16:00:00 2019-11-21 17:00:00 Astronomy Colloquium - Rachel Bezanson

The Formation of Massive Galaxies: Deep, High-Redshift Spectroscopy from the LEGA-C Survey and Beyond

Rachel Bezanson - University of Pittsburgh

Today’s massive elliptical galaxies are primarily red-and-dead, dispersion supported ellipticals. The physical process(es) driving the shutdown or “quenching” of star formation in these galaxies remains one of the least understood aspects of galaxy formation and evolution. Although today’s spiral and elliptical galaxies exhibit a clear bimodality in their structures, kinematics, and stellar populations, it may be that the quenching and structural transformation do no occur simultaneously. In this talk, I will focus on results from the Large Early Galaxy Astrophysics Census (LEGA-C) survey of massive galaxies at z~0.8. I will show that early quiescent galaxies, observed much closer to their quenching epoch at z~1, retain significant rotational support (~twice as much as local ellipticals). This suggests that the mechanisms responsible for shutting down star formation do not also have to destroy ordered motion in massive galaxies; the increased dispersion support could occur subsequently via hierarchical growth and minor merging. Finally, I will discuss prospects for extending spatially resolved spectroscopic studies of galaxies immediately following quenching with JWST and eventually 30-m class telescopes. 

E0040 Scott Laboratory Department of Astronomy astronomy@osu.edu America/New_York public
Description

The Formation of Massive Galaxies: Deep, High-Redshift Spectroscopy from the LEGA-C Survey and Beyond

Rachel Bezanson - University of Pittsburgh

Today’s massive elliptical galaxies are primarily red-and-dead, dispersion supported ellipticals. The physical process(es) driving the shutdown or “quenching” of star formation in these galaxies remains one of the least understood aspects of galaxy formation and evolution. Although today’s spiral and elliptical galaxies exhibit a clear bimodality in their structures, kinematics, and stellar populations, it may be that the quenching and structural transformation do no occur simultaneously. In this talk, I will focus on results from the Large Early Galaxy Astrophysics Census (LEGA-C) survey of massive galaxies at z~0.8. I will show that early quiescent galaxies, observed much closer to their quenching epoch at z~1, retain significant rotational support (~twice as much as local ellipticals). This suggests that the mechanisms responsible for shutting down star formation do not also have to destroy ordered motion in massive galaxies; the increased dispersion support could occur subsequently via hierarchical growth and minor merging. Finally, I will discuss prospects for extending spatially resolved spectroscopic studies of galaxies immediately following quenching with JWST and eventually 30-m class telescopes.