2016/05/31 by Julian B. Muñoz, Ely D. Kovetz, Liang Dai +1 · 1 citation
Physics and Astronomy · #astro-ph.CO #astro-ph.HE #hep-ph
paper · pdf · doi:10.1103/physrevlett.117.091301
published as Phys. Rev. Lett. 117, 091301 (2016) · 6 Pages, 4 Figures. Published in PRL
arxiv created 2016/08/25 · arxiv updated 2016/08/31
The possibility that part of the dark matter is made of massive compact halo objects (MACHOs) remains poorly constrained over a wide range of masses, and especially in the 20-100 M_\odot window. We show that strong gravitational lensing of extragalactic fast radio bursts (FRBs) by MACHOs of masses larger than ∼20 M_\odot would result in repeated FRBs with an observable time delay. Strong lensing of an FRB by a lens of mass ML induces two images, separated by a typical time delay ∼ few ×(ML/30 M_\odot) milliseconds. Considering the expected FRB detection rate by upcoming experiments, such as CHIME, of 104 FRBs per year, we should observe from tens to hundreds of repeated bursts yearly, if MACHOs in this window make up all the dark matter. A null search for echoes with just 104 FRBs, would constrain the fraction f\rm DM of dark matter in MACHOs to f\rm DM\lesssim 0.08 for ML\gtrsim 20 M_\odot.