Detecting Dark Matter Substructures and Gravitational Waves with Fast Radio Burst Timing
Dr. Huangyu Xiao
Associate Fellow, KICP
Fermilab and University of Chicago
We propose measuring the arrival time difference of Fast Radio Bursts (FRBs) along two adjacent sightlines as a new probe to dark matter substructures and gravitational waves. The FRB timing requires placing radio telescopes in space that will observe the same FRB source. We find that two radio dishes separated by 20 AU can be sensitive to the enhancement of small-scale structures from large masses down to 10^-8 Solar masses predicted in the QCD axion dark matter scenario or in an early epoch of matter-domination with a reheating temperature up to 60 MeV. It can also fill the so-called micro-HZ gap of gravitational wave detection where current or proposed GW detections are not sensitive. I will also discuss alternative approaches if the ambitious space mission is not funded.