TAPIR Seminar

Gravitational lensing by matter clumps can magnify various transient events in the sky, making them more detectable from the higher redshift Universe. For one example, chirping gravitational waves from stellar-mass black hole binary mergers, as first detected by LIGO recently, may be magnified by intervening galaxies. In the absence of electromagnetic counterpart, however, lensing magnification can bias the determination of binary mass and redshift, which needs to be accounted for when testing binary formation models through merger statistics. As another example, multiply-imaged fast radio bursts (FRB) may be identified from repetition in their time-domain signature, if those have extragalactic origin. In particular, using gravitational microlensing, forthcoming FRB surveys will have the capacity to probe compact dark matter of 20-100 solar masses, therefore closing an interesting window that has remained poorly constrained by other observations.