A Measurement of Circumgalactic Gas around Nearby Galaxies Using Fast Radio Bursts

Abstract

The distribution of gas in the circumgalactic medium (CGM) of galaxies of all types is poorly constrained. Foreground CGMs contribute an extra amount to the dispersion measure (DM) of fast radio bursts (FRBs). We measure this DM excess for the CGMs of 1011–1013 M ⊙ halos using the CHIME/FRB first data release, a halo mass range that is challenging to probe in any other way. Because of the uncertainty in the FRBs’ angular coordinates, only for nearby galaxies is the localization sufficient to confidently associate them with intersecting any foreground halo. Thus we stack on galaxies within 80 Mpc, optimizing the stacking scheme to approximately minimize the stack’s variance and marginalize over uncertainties in FRB locations. The sample has 20–30 FRBs intersecting halos with masses of 1011–1012 M ⊙ and also of 1012–1013 M ⊙, and these intersections allow a marginal 1σ–2σ detection of the DM excess in both mass bins. The bin of 1011–1012 M ⊙ halos also shows a DM excess at 1–2 virial radii. By comparing data with different models for the CGM gas profile, we find that all models are favored by the data up to 2σ level compared to the null hypothesis of no DM excess. With 3000 more bursts from a future CHIME data release, we project a 4σ detection of the CGM. Distinguishing between viable CGM models by stacking FRBs with CHIME-like localization would require tens of thousands of bursts.

Measuring the Variance of the Macquart Relation in Redshift–Extragalactic Dispersion Measure Modeling

“…Current methods that are employed to constrain the variance of the z-DM EG involve stacking analyses and leveraging twopoint statistics. Weighted stacking can measure DM excess by binning FRB DM measurements by the halo mass the FRB intercepts; however, it loses efficacy at high redshift (z > 0.1; Wu & McQuinn 2023). The latter works by correlating galaxy survey catalogs (binned along redshift) and FRB catalogs (binned along DM; Rafiei-Ravandi et al 2020).…”

The Demographics, Stellar Populations, and Star Formation Histories of Fast Radio Burst Host Galaxies: Implications for the Progenitors

“…The FRB signal properties, namely their dispersion measure (DM), rotation measure (RM), duration, spectrotemporal morphology, and polarization, provide key information on their central engines, and serve as important probes of the intervening ionized matter (e.g., Michilli et al 2018;Hessels et al 2019;Hilmarsson et al 2021;Mannings et al 2022;Ryder et al 2022;Wu & McQuinn 2023;Cook et al 2023;Ocker et al 2023). However, these signals alone provide only a highly model-dependent, low-precision estimate of the distance to the FRB, making it difficult or impossible to infer the parent stellar populations and FRB energetics directly.…”

A Unified Model for the Coevolution of Galaxies and Their Circumgalactic Medium: The Relative Roles of Turbulence and Atomic Cooling Physics

“…At higher redshifts, there are a wealth of constraints from both absorption line studies (e.g., Steidel et al 2010;Bordoloi et al 2011;Rudie et al 2012Rudie et al , 2019Burchett et al 2019;Chen et al 2020) and CGM emission maps (e.g., Wisotzki et al 2016Wisotzki et al , 2018Leclercq et al 2017Leclercq et al , 2020. Even more CGM constraints are expected in the future from observations of the Sunyaev-Zel'dovich effect around galaxyscale halos (Mroczkowski et al 2019), localized fast radio bursts (Prochaska & Zheng 2019;Wu & McQuinn 2023), and the next generation of ground-and space-based observatories.…”