Wednesday, March 30, 2016
4:00 pm
Cahill, Hameetman Auditorium – Cahill Center for Astronomy and Astrophysics

Astronomy Colloquium

Galaxy Death and the Role of “Red Geysers"
Kevin Bundy, Kavli IPMU, Tokyo

Surveys of the distant universe show that star formation in very massive galaxies begins to die out nearly 10 billion years ago.  This mysterious trend continues to the present day, making "red and dead" systems the dominant population among galaxies larger than the Milky Way.  Despite the importance of star formation "quenching," its physical origin as well as the mechanisms responsible for preventing star formation at late times is still under debate. Addressing this question is a key goal of MaNGA (Mapping Nearby Galaxies at Apache Point Observatory), a core program in the 4th generation Sloan Digital Sky Survey that is obtaining resolved spectroscopy for 10,000 nearby galaxies.  Already the largest integral-field spectroscopic survey ever conducted with over 2000 galaxies observed, MaNGA's rich data set is providing new insight on the physics behind galaxy death.  I will present our discovery of surprisingly common "red geysers," elliptical galaxies that harbor large-scale ionized winds, likely driven by low-level accretion onto supermassive black holes.  As illustrated by a prototypical example, there is sufficient power in these winds to turbulently heat ambient gas and prevent star formation at late times.  Episodes of red geyser activity (we estimate they occur every several 100 Myr) may play a critical role in the final stages of galaxy evolution.

Contact Althea E. Keith aek@astro.caltech.edu at 626-395-4973
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