2024/05/23 by Jakob T. Faber, Vikram Ravi, Faber, Jakob T. +35
Physics and Astronomy · #Astrophysics of Galaxies (astro-ph.GA) #FOS: Physical sciences #High Energy Astrophysical Phenomena (astro-ph.HE) #Pulsars and Gravitational Waves Research
paper · pdf · doi:10.48550/arxiv.2405.14182
openalex publication_date 2024/05/23 · openalex created_date 2024/05/25 · openalex updated_date 2026/08/01
We present a multi-wavelength study of the apparently non-repeating, heavily scattered fast radio burst, FRB 20221219A, detected by the Deep Synoptic Array 110 (DSA-110). The burst exhibits a moderate dispersion measure (DM) of 706.7+0.6-0.6 pc~cm-3 and an unusually high scattering timescale of τobs = 19.2-2.7+2.7 ms at 1.4 GHz. We associate the FRB with a Milky Way-like host galaxy at zhost = 0.554 of stellar mass log10(M⋆, host) = 10.20+0.04-0.03 ~M_\odot. We identify two intervening galaxy halos at redshifts zigh1 = 0.492 and zigh2 = 0.438, with low impact parameters, bigh1 = 43.0-11.3+11.3 kpc and bigh2 = 36.1-11.3+11.3 kpc, and intermediate stellar masses, log10(M⋆, igh1) = 10.01+0.02-0.02 ~M_\odot and log10(M⋆, igh2) = 10.60+0.02-0.02 ~M_\odot. The presence of two such galaxies suggests that the sightline is significantly overcrowded compared to the median sightline to this redshift, as inferred from the halo mass function. We perform a detailed analysis of the sightline toward FRB 20221219A, constructing both DM and scattering budgets. Our results suggest that, unlike most well-localized sources, the host galaxy does not dominate the observed scattering. Instead, we posit that an intersection with a single partially ionized cloudlet in the circumgalactic medium of an intervening galaxy could account for the substantial scattering in FRB 20221219A and remain in agreement with typical electron densities inferred for extra-planar dense cloud-like structures in the Galactic and extragalactic halos (e.g., high-velocity clouds).