First Constraints on Compact Dark Matter from Fast Radio Burst Microstructure

Understand

Despite existing constraints, it remains possible that up to $35\%$ of all dark matter is comprised of compact objects, such as the black holes in the 10-100\,M$_\odot$ range whose existence has been confirmed by LIGO.

• The strong gravitational lensing of transients such as FRBs and GRBs has been suggested as a more sensitive probe for compact dark matter than intensity fluctuations observed in microlensing experiments.
• Recently ASKAP has reported burst substructure down to $15\mu$s timescales in FRBs in the redshift range $0.3-0.5$.
• We investigate here the implications of this for the detectability of compact dark matter by FRBs.