Jamie McCullough is a postdoctoral researcher in observational cosmology at Princeton University, using the measurements of galaxy shapes to trace the large-scale structure of the universe and the growth of that structure with cosmic time. She works with weak gravitational lensing surveys like the Dark Energy Survey and Rubin, and spectroscopic surveys (4MOST, DESI) to better understand how these measurements are impacted by the astrophysics and evolution of galaxies.
Title: Breaking astrophysical barriers to weak lensing surveys: Informing photometric redshifts, intrinsic alignments, and baryon feedback
Abstract:
Weak gravitational lensing is a powerful probe of large-scale cosmic structure, examining galaxy shapes after they are minutely distorted through the cosmic web. Cosmological precision from lensing measurements are limited most strongly by our ability to model astrophysical effects—how galaxies intrinsically align with one another, baryon feedback, and uncertainty in the relation between galaxy colors and their distance. With the advent of the most comprehensive weak lensing surveys to date (Rubin, Euclid, Roman), I will discuss these systematics and spectroscopic efforts to constrain many of them in the context of DESI and 4MOST, with lensing case studies in the Dark Energy Survey (DES). I propose that data-driven approaches to modeling intrinsic alignments and baryon feedback will enable next-generation experiments to probe the smallest scales and therefore produce the tightest constraints on dark energy and large-scale structure.