Void Lensing as a Test of Gravity

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We investigate the potential of weak lensing by voids to test for deviations from General Relativity.

• We calculate the expected lensing signal of a scalar field with derivative couplings, finding that it has the potential to boost the tangential shear both within and outside the void radius.
• We use voids traced by Luminous Red Galaxies in SDSS to demonstrate the methodology of testing these predictions.
• We find that the void central density parameter, as inferred from the lensing signal, can shift from its GR value by up to 20% in some galileon gravity models.