The FRB20190520B Sightline Intersects Foreground Galaxy Clusters

Abstract

The repeating fast radio burst FRB20190520B is an anomaly of the FRB population thanks to its high dispersion measure (DM$=1205$pc/cc) despite its low redshift of $z_{\mathrm{frb}}=0.241$. This excess has been attributed to a large host contribution of $D{M}_{host}\approx 900$pc/cc, far larger than any other known FRB. In this paper, we describe spectroscopic observations of the FRB20190520B field obtained as part of the FLIMFLAM survey, which yielded 701 galaxy redshifts in the field. We find multiple foreground galaxy groups and clusters, for which we then estimated halo masses by comparing their richness with numerical simulations. We discover two separate $M_{halo}>10^{14}{M}_{\odot }$ galaxy clusters, at $z=0.1867$ and $z=0.2170$, respectively, that are directly intersected by the FRB sightline within their characteristic halo radius \rvir{}. Subtracting off their estimated DM contributions as well that of the diffuse intergalactic medium, we estimate a host contribution of $D{M}_{host}=430_{-220}^{+140}$pc/cc or $D{M}_{host}=280_{-170}^{+140}$pc/cc (observed frame) depending on whether we assume the halo gas extends to $r_{200}$ or $2\times r_{200}$. This significantly smaller $D{M}_{host}$ -- no longer the largest known value -- is now consistent with H$\alpha$ emission measures of the host galaxy without invoking unusually high gas temperatures. Combined with the observed FRB scattering timescale, we estimate the turbulent fluctuation and geometric amplification factor of the scattering layer to be $\tilde{F}G\approx 4.5-11(\mathrm{p}{\mathrm{c}}^2\mathrm{km}{)}^{-1/3}$, suggesting most of the gas is close to the FRB host. This result illustrates the importance of incorporating foreground data for FRB analyses, both for understanding the nature of FRBs and to realize their potential as a cosmological probe.

Accepted by ApJL. Interactive figure included (link in text). Note numerical values have changed from v1

References in corpus (18)

• Array Programming with NumPy
• The Astropy Project: Sustaining and Growing a Community-oriented Open-source Project and the Latest Major Release (v5.0) of the Core Package
• A New Electron Density Model for Estimation of Pulsar and FRB Distances
• The Five-Hundred-Meter Aperture Spherical Radio Telescope (FAST) Project
• The Host Galaxy and Redshift of the Repeating Fast Radio Burst FRB 121102
• A census of baryons in the Universe from localized fast radio bursts
• Probing Galactic Halos with Fast Radio Bursts
• The stellar mass-halo mass relation of isolated field dwarfs: a critical test of $\Lambda$CDM at the edge of galaxy formation
• OzDES multifibre spectroscopy for the Dark Energy Survey: Three year results and first data release
• Fast Radio Bursts and cosmological tests
• Groups of galaxies in the SDSS Data Release 5. A group-finder and a catalogue
• Intergalactic medium dispersion measures of fast radio bursts estimated from IllustrisTNG simulation and their cosmological applications
• An FRB Sent Me a DM: Constraining the Electron Column of the Milky Way Halo with Fast Radio Burst Dispersion Measures from CHIME/FRB
• Multi-Object Spectroscopy Field Configuration by Simulated Annealing
• Bayesian inference of cosmic density fields from non-linear, scale-dependent, and stochastic biased tracers
• Circumgalactic Oxygen Absorption and Feedback
• Deep Synoptic Array science: Two fast radio burst sources in massive galaxy clusters
• The dispersion measure and scattering of FRBs: Contributions from the intergalactic medium, foreground halos, and hosts

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