Accounting for Baryons in Dark Energy Constraints: From DES to LSST

University Of Pittsburgh, Pittsburgh PA

Investigators

Abstract

The goal of this program is to use simulations to understand corrections to the distribution of weak gravitational lensing effects caused by the particles that make up normal matter (known as "baryons"); gravitational lensing is the process in which large amounts of matter bend the light coming from more distant objects, located beyond the matter distributions. These simulations would reduce systematic errors for next-generation studies of the "dark energy" phenomenon that causes the accelerating expansion of the universe that use weak lensing. Broader impacts are substantial and include training of undergraduate and graduate students, as well as public outreach. Dr. Zentner will give public lectures at the Allegheny Observatory, conduct educational events at the Carnegie Science Center Buhl Academy, organize the University of Pittsburgh's Astronomy Outreach Program, and lecture at continuing education events for public school teachers. The program addresses the issue that all weak lensing surveys probe small scales where baryonic effects become important in the interpretation of dark energy studies, and includes carefully planned steps to deal with these effects. A key strength is the use of multiple approaches to model the effects of baryons: parameterizing baryonic effects by modifying density profiles; using blind analyses of simulations with different baryonic effects; cluster expansion methods; and Lagrangian methods.