Fast radio bursts as probes of feedback from active galactic nuclei

• Main Authors: Batten, A.J (Author), Duffy, A.R (Author), Flynn, C. (Author), Gupta, V. (Author), Ryan-Weber, E. (Author), Wijers, N. (Author)
• Format: Article
• Language: English
• Published: Oxford University Press 2022
• Subjects: hydrodynamics; intergalactic medium; methods: numerical; radio continuum: general
• Online Access: View Fulltext in Publisher

 Fast radio bursts (FRBs) are a promising tool for studying the low-density universe as their dispersion measures (DM) are extremely sensitive probes of electron column density. Active galactic nuclei (AGN) inject energy into the intergalactic medium, affecting the DM and their scatter. To determine the effectiveness of FRBs as a probe of AGN feedback, we analysed three different AGN models from the EAGLE simulation series. We measured the mean DM-redshift relation, and the scatter around it, using 2.56 × 108 sightlines at 131 redshift (z) bins between 0 ≤ z ≤ 3. While the DM-redshift relation itself is highly robust against different AGN feedback models, significant differences are detected in the scatter around the mean: weaker feedback leads to more scatter. We find that ∼104 localized FRBs are needed to discriminate between the scatter in standard feedback and stronger, more intermittent feedback models. The number of FRBs required is dependent on the redshift distribution of the detected population. A lognormal redshift distribution at z = 0.5 requires approximately 50 per cent fewer localized FRBs than a distribution centred at z = 1. With the Square Kilometre Array expected to detect >103 FRBs per day, in the future, FRBs will be able to provide constraints on AGN feedback. © 2022 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society.