Astrophysics Luncheon Seminar
Cosmic Shear Measurement Challenges
Presented by Joe Zuntz
University of Manchester
Monday, February 9, 2015
12:00 noon in 169-336
Cosmic shear, the measurement of weak field lensing of galaxy light by intervening gravitational fields, is the most promising probe of cosmic structure for the next generation of grand surveys, and can give us a handle on the history of dark energy and provide powerful tests of General Relativity.
In this talk I'll cover the basic physics and cosmology of weak lensing, and the current status and the significant challenges facing this current and future work. I'll focus on one of the major problems, the measurement and calibration of galaxy image shapes to determine their gravitational distortion. I'll show why this is such a painfully hard problem, and go through the progress that's been made in particular through our work on model-fitting methods.
If time permits I'll also briefly discuss CosmoSIS, our framework for connecting together and sampling from likelihoods like the ones from cosmic shear under a wide variety of different systematics and physical models.
JPL Contact: Tim Eifler (4-5008)