Dr. Reinabelle Reyes to give a talk at Manila Observatory: “Testing general relativity on cosmological scales”

Dr. Reinabelle Reyes

In connection with the Manila Observatory’s brown bag seminar series, please be informed that Ms. Reina Reyes of Kavli Institute for Cosmological Physics, University of Chicago will deliver a lecture as part of this series on Friday, 17 February at the Klima Conference Room of the Manila Observatory from 11:30am to 12:30pm.

Was Einstein wrong? Testing general relativity on cosmological scales using weak gravitational lensing and galaxy peculiar velocities

Abstract

Although general relativity (GR) underlies modern cosmology, its validity on cosmological length scales has yet to be stringently tested. Moreover, the breakdown of GR on large scales can provide an alternative explanation for the observed accelerated expansion of the Universe, which the current cosmological model attributes to the effect of a mysterious gravitationally-repulsive dark energy.

Fortunately, using cosmological observations from current and upcoming galaxy surveys, we have the power to detect modifications to GR on large scales. In this talk, I will present a robust and model-independent observational test using imaging and spectroscopy of ~70,000 luminous red galaxies from the Sloan Digital Sky Survey (SDSS). This test combines three different probes of the large-scale structure– weak gravitational lensing, redshift distortions, and galaxy clustering– to obtain a probe of gravity that is insensitive to uncertain astrophysical parameters. I will show that our results confirm the predictions of GR on scales of tens of megaparsecs (~108 light years), provide interesting constraints on modified theories of gravity, and serve as a proof of concept for upcoming galaxy surveys,
which are expected to yield more stringent constraints.