We use the measured scattering timescales of Fast Radio Bursts (FRBs) from the CHIME catalog to derive an upper limit on the magnetic field on sub-kpc scales in the intergalactic medium (IGM). A nonmagnetized, photoionized IGM is insufficient to explain the turbulent scattering at all redshifts, with a Warm-Hot component being marginally consistent with the data at z∼1. Accounting for the lower envelope of the temporal smearing distribution with a nonzero magnetic field leads to upper limits B<10−30 nG on scales of 0.07-0.20 kpc in the IGM at z∼1−2. Our work introduces a novel technique to constrain small-scale magnetic fields in the IGM, in a regime unexplored by the Rotation and Dispersion Measures of FRBs.
@article{arxiv.2301.08259,
title = {A new limit on intergalactic magnetic fields on sub-kpc scales from fast radio bursts},
author = {Hamsa Padmanabhan and Abraham Loeb},
journal= {arXiv preprint arXiv:2301.08259},
year = {2023}
}
Comments
7 pages, 3 figures, 1 table; accepted for publication in ApJL