Gravitational Microlensing of Gamma Ray Bursts at Medium Optical Depth

Abstract

Gravitational lensing of a gamma ray burst (GRB) by a single point mass will produce a second, delayed signal. Several authors have discussed using microlensed GRBs to probe a possible cosmological population of compact objects. We analyse a closely related phenomenon; the effect of microlensing by low to medium optical depth in compact objects on the averaged observed light-curve of a sample of GRBs. We discuss the cumulative measured flux as a function of time resulting from delays due to microlensing by cosmological compact objects. The time-scale and curvature of this function describe unique values for the compact object mass and optical depth. For GRBs with durations larger than the detector resolution, limits could be placed on the mass and optical depth of cosmological compact objects. The method does not rely on the separation of lensed bursts from those which are spatially coincident.

6 pages, 4 figures. Accepted for publication in MNRAS

References in corpus (2)

• The MACHO Project: Microlensing Results from 5.7 Years of LMC Observations
• Discovery of high proper motion ancient white dwarfs: nearby massive compact halo objects?

Cited by in corpus (4)

• Strong gravitational lensing of explosive transients
• Evidence for an intermediate-mass black hole from a gravitationally lensed gamma-ray burst
• FRBs Lensed by Point Masses II. The multi-peaked FRBs from the point view of microlensing
• Gravitational Microlensing Time Delays at High Optical Depth: Image Parities and the Temporal Properties of Fast Radio Bursts