Special seminar

Speaker: Zack Slepian (UCBerkeley)
Title: Revitalizing the Galaxy 3-Point Correlation Function to Probe Dark Energy
Date: Wed, Jan 17, 2018, 11:00 - 12:00
Place: Seminar Room A
Abstract: 3-D maps of the distribution of galaxies in our Universe, such as the Sloan Digital Sky Survey (SDSS), have revealed the cosmological parameters with unprecedented precision. These have yielded percent-level constraints on the behavior of dark energy using the imprint of Baryon Acoustic Oscillations as a standard ruler to map the Universe's expansion history. In the next five years Dark Energy Spectroscopic Instrument (DESI) will map a factor of 30 more galaxies (30 million) than SDSS and vastly increase the precision of constraints on dark energy. To fully leverage this rich upcoming dataset, groundbreaking analysis techniques will be vital.

I will present a fast, multipole-based algorithm to compute the galaxy 3-Point Correlation Function, discuss modeling this observable, and then show constraints on the cosmic expansion history from the SDSS Baryon Oscillation Spectroscopic Survey (BOSS) sample of 800,000 Luminous Red Galaxies. I will then turn to anisotropic clustering, an important method that uses redshift-space distortions to probe modified gravity (another possible explanation for accelerated cosmic expansion). I will present an extension of the multipole 3PCF algorithm suitable for making the first measurement of this signal, and an implementation scaled to the full Cori supercomputer at Berkeley Lab's National Energy Research Supercomputing Center. I will wrap up with discussion of higher-point statistics in this framework and prospects for DESI.