CCAPP Seminar: Alexie Leauthaud (UC Santa Cruz)

Galaxies and Dark Matter: Cosmology, Correlations, and Conundrums

 

I will present a variety of new results on the connection between super massive galaxies and

their dark matter halos. First, I will discuss the “lensing is low” puzzle. This is the observation

that the lensing signal around luminous red galaxies from the BOSS survey is lower by 20-

30% than predicted by galaxy clustering. Second, I will show how not only galaxy mass, but

also the shapes of their light profiles are connected with halo mass (the M10-M100 plane). I

will connect this observation with the assembly history of massive galaxies and the growth of

their in-situ and ex-situ components. I will present comparisons between the light profiles of

massive galaxies in the Hyper-Surime Cam surveys and predictions from the Illustris and

TNG simulations. I will briefly present new results on the accuracy and precision of detections

of the splash-back radius of dark matter halos. Finally, I will discuss future applications with

the DESI survey which is currently commissioning and will soon collect science verification

data.