Gravitational lensing of fast radio bursts (FRBs) offers an exciting avenue
for several cosmological applications. However, it is not yet clear how many
such events future surveys will detect nor how to optimally find them. We use
the known properties of FRBs to forecast detection rates of gravitational
lensing on delay timescales from microseconds to years, corresponding to lens
masses spanning fifteen orders of magnitude. We highlight the role of the FRB
redshift distribution on our ability to observe gravitational lensing. We
consider cosmological lensing of FRBs by stars in foreground galaxies and show
that strong stellar lensing will dominate on microsecond timescales. Upcoming
surveys such as DSA-2000 and CHORD will constrain the fraction of dark matter
in compact objects (e.g. primordial black holes) and may detect millilensing
events from intermediate mass black holes (IMBHs) or small dark matter halos.
Coherent all-sky monitors will be able to detect longer-duration lensing events
from massive galaxies, in addition to short time-scale lensing. Finally, we
propose a new application of FRB gravitational lensing that will measure
directly the circumgalactic medium of intervening galaxies.
Preprint
Subjects: Astrophysics - Cosmology and Nongalactic Astrophysics; Astrophysics - High Energy Astrophysical Phenomena