"Old Galaxies, New Surprises" by Alexie Leauthaud (UC Santa Cruz)

Thursday, April 5, 2018 - 4:00pm to 5:00pm
Physics and Astronomy Colloquium

Thursdays, 4:00-5:00 pm

1-434 Physics and Astronomy (map)
Reception from 3:30-4:00 p.m.
(unless otherwise posted)

Guest Speaker: Alexi Leauthaud (University of California, Santa Cruz)

Talk Title: “Old Galaxies, New Surprises”




I will present new results from the ongoing Hyper Suprime Cam survey currently being carried out by Subaru. The HSC survey is an unprecedented effort to map 1400 deg^2 in 5 bands to i~26. This unique combination of depth and area enables us to study the individual light profiles of several thousand super massive galaxies (M*>11.6 Msun) to 100 kpc and beyond. We show that massive galaxies are not self similar and that instead their light profiles are diverse. This diversity is not random: using weak gravitational lensing we make a remarkable discovery. There is a tight correlation between the shapes of galaxy light profiles and their host dark matter halo mass. Deep imaging is critical for measuring the total light from these galaxies. With better luminosity measurements in hand, I will show that there is a much tighter relation between the luminosities of super massive galaxies and dark matter halo mass that previously recognized.  Finally, I will discuss how our results have the potential to transform optical galaxy cluster detection and the way we use cluster surveys to constrain dark energy.

For more information, contact Jay Hauser

We thank the following people for their contributions to the wine fund for the post-colloquium reception:
Prof. Dolores Bozovic, Prof. Robijn Bruinsma, Prof. Wesley Campbell, Prof. Bob Cousins, Prof. Andrea Ghez, Prof. Jay Hauser, Prof. Eric Hudson, Robert Huff, Prof. HongWen Jiang, Prof. Alex Kusenko, Prof. John Miao, Prof. George Morales, Prof. Pietro Musumeci, Prof. Christoph Niemann, Prof. Rene Ong, Prof. James Rosenzweig, Prof. David Saltzberg, and Prof. Jean Turner.

1-434 PAB