http://arxiv.org/abs/2005.07533
Strong lensing time delay measurements provide a valuable and almost model-independent tool for cosmological investigations. In this work we recognize that they also carry information on the strength of the gravitational coupling at the redshift of the lens, and thus could be in principle used to test the equivalence principle on extragalactic scales. For the case of an extended lens with a static mass distribution we explicitly derive an analytical relation between $\dot{G}/G$ and the relative variation of the time delay. For illustrative purpose, we apply our formula to the light curves of multiple images of the quasar WFI2033-4723 and simulated ones, which results in weak constraints on the variation of $\dot{G}/G$ of order $10^{-2} \, yr^{-1}$ in the best scenario. Finally we briefly discuss how those constraints can be improved in the next future.
L. Giani and E. Frion
Mon, 18 May 20
19/43
Comments: 12 pages, no figures, comments are welcome
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