Light Curve Test of GRB 200716C as a Gravitationally Lensed Echo

Abstract

Abstract A gravitational lens can imprint distinct features on the light curve of a gamma-ray burst (GRB). Most prominently, when creating multiple images, the light curves for all images should be identical, within a scale factor in amplitude. For GRB images that are bright enough to have significant counts in multiple time bins, the similarity of the light curves can be assessed with a straightforward χ 2 test. In response to a recent claim that the two pulses in GRB 200716C are lensed images of the same pulse, such a χ 2 test was computed. The test indicated that the likelihood that the two pulses are images of the same parent pulse is less than 0.218%, differing at about the 3.1σ confidence level. Therefore, under the given assumptions, GRB 200716C is not a compelling example of gravitational lensing.