A Comparison of G Inside and Outside of Cosmic Voids

Various models of modified gravity invoke ``screening'' mechanisms that are sensitive to the value of the local gravitational potential. This could have observable consequences in the internal kinematics of galaxies. Motivated by this prospect, we have conducted a comparison of the observable properties of luminous red galaxies (LRGs) inside and outside of voids in the cosmic large scale structure. We used archival measurements of line widths, luminosities, redshifts, colors, and positions of galaxies in conjunction with recent void catalogs to construct comparison LRG samples inside and outside of voids. We use fits to the well-established fundamental plane of elliptical galaxies to constrain any differences between the aggregate properties of the two samples. We will present preliminary constraints on the fractional difference in the value of the gravitational constant G that governs the internal kinematics of elliptical galaxies within and outside of cosmological voids. This places observational constraints on screened gravity theories.