The Circumgalactic Medium with Local Universe Fast Radio Bursts: Evidence of Strong Active Galactic Nucleus Feedback in a Massive Elliptical Galaxy
Year: 2026
Type: article
Abstract: Modern cosmology and galaxy formation rely on an understanding of how cosmic baryons are distributed, a significant portion of which exists in the diffuse gas confined to halos. Fast radio bursts (FRBs) are a promising probe of the Universe’s ionized gas. At low redshift, the contribution to the dispersion measure (DM) from the intergalactic medium (IGM) and intervening halos is subdominant, allowing us to study the circumgalactic medium (CGM) of the host galaxies, if the host interstellar medium (ISM) can be sufficiently suppressed. We select a sample of five local Universe FRBs with host halos spanning a wide range in mass (∼10 11−13 M ⊙ ), and with indicators that host ISM DM is negligible. We use these FRBs to constrain the CGM in each halo by comparing to simulations and measuring the CGM mass assuming a range of spherical gas profiles. We find that one of our sources, the only massive elliptical host galaxy, strongly disfavors low feedback scenarios in simulations, and has been evacuated of its baryons (∼ 10% of the cosmological average Ω b Ω m within R vir ). This galaxy shows evidence of a past episode of active galactic nucleus (AGN) activity, consistent with the picture of strong AGN feedback in galaxy group-scale halos. The gas mass measurements for the other sources tentatively support more baryon retention in L * galaxies compared to group-scale halos. Finally, we demonstrate that a large sample of local Universe FRBs will enable precision measurements of halo gas.
Authors: Samuel McCarty, Liam Connor, Ralf M. Konietzka
Institution: Center for Astrophysics Harvard & Smithsonian
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,400
OpenAlex ID: W7203670403