Strong Lensing of Gamma Ray Bursts as a Probe of Compact Dark Matter

Understand

Compact dark matter has been efficiently constrained in the M <~ 10 M_sun mass range by null searches for microlensing of stars in nearby galaxies.

• Here we propose to probe the mass range M >~ 10 M_sun by seeking echoes in gamma-ray-burst light curves induced by strong lensing.
• We show that strong gravitational lensing of gamma ray bursts (GRBs) by massive compact halo objects (MACHOs) generates superimposed GRB images with a characteristic time delay of >~ 1 ms for M >~ 10 M_sun.
• Using dedicated simulations to capture the relevant phenomenology of the GRB prompt emission, we calculate the signal-to-noise ratio required to detect GRB lensing events as a function of the flux ratio and time delay between the lensed images.