A New Independent Limit on the Cosmological Constant/Dark Energy from the Relativistic Bending of Light by Galaxies and Clusters of Galaxies

Abstract

We derive new limits on the value of the cosmological constant, $Λ$, based on the Einstein bending of light by systems where the lens is a distant galaxy or a cluster of galaxies. We use an amended lens equation in which the contribution of $Λ$ to the Einstein deflection angle is taken into account and use observations of Einstein radii around several lens systems. We use in our calculations a Schwarzschild-de Sitter vacuole exactly matched into a Friedmann-Robertson-Walker background and show that a $Λ$-contribution term appears in the deflection angle within the lens equation. We find that the contribution of the $Λ$-term to the bending angle is larger than the second-order term for many lens systems. Using these observations of bending angles, we derive new limits on the value of $Λ$. These limits constitute the best observational upper bound on $Λ$ after cosmological constraints and are only two orders of magnitude away from the value determined by those cosmological constraints.

5 pages, 1 figure, matches version published in MNRAS