Probing the Metallicity Dependence of Fast Radio Burst Progenitors with CHIME/FRB Outrigger Dwarf Host Galaxies
Year: 2026
Type: preprint
Abstract: Using the fast radio bursts (FRBs) localized with the CHIME/FRB Outriggers between February and October 2025, we conduct a systematic search for dwarf host galaxies. We identify and characterize eight host galaxies for one repeating and seven apparently non-repeating FRBs, newly classifying five hosts as dwarfs with stellar masses of $\log(M_\ast/M_\odot) \approx 8.1-9.1$. We measure their gas-phase metallicities and, when combined with hosts from the literature, finding that repeating and non-repeating FRBs have statistically distinct metallicity distributions. Non-repeating FRBs inhabit relatively metal-rich environments ($12 + \rm log( O/H) \gtrsim 8.35$) across the full observed mass range, while repeating FRBs have significant preference for dwarf galaxies with $12 + \rm log( O/H) \lesssim 8.35$. Almost all repeaters associated with persistent radio sources (PRSs) are in dwarfs with $12 + \rm log( O/H) \lesssim 8.15$, suggesting a connection between repeaters in metal-poor dwarf environments and PRS formation. We also calculate the host dispersion measure ($\mathrm{DM}_{\rm host}$), Faraday rotation measure ($\mathrm{RM}_{\rm host}$), and scattering timescale ($τ_{\rm host,1~GHz}$) for 54, 37, and 24 FRBs, respectively, including both our sample and FRBs in the literature. We find no significant ($>3σ$) correlation between host metallicity and $\mathrm{DM}_{\rm host}$, $\mathrm{RM}_{\rm host}$, or $τ_{\rm host,1~GHz}$. The distinct host metallicities of apparently non-repeating and repeating FRBs may reflect metallicity-dependent massive-star evolution, with repeating FRBs and PRSs requiring more extreme magnetar birth spins than the predominantly non-repeating FRB population.
Source: arXiv (Cornell University)
Authors: Dong, Y., Fong, W., Nimmo, K., Loudas, N., Andersen, B. C., Andrew, S., Cai, A., Chatterjee, S., Cook, A. M., Curtin, A. P., Eftekhari, T., Gaensler, B. M., Hessels, J., Kaspi, V. M., Khan, A., Leung, C., Mas-Ribas, L., Masui, K., Moroianu, A., Pearlman, A. B., Prochaska, J. X., Sammons, M. W., Scholz, P., Shin, K., Simha, S., Woodland, M., Zhuang, Z.
Institution: Northwestern University
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Funders: National Science Foundation, National Aeronautics and Space Administration, Alfred P. Sloan Foundation, Gordon and Betty Moore Foundation, Research Corporation for Science Advancement, Adolph C. and Mary Sprague Miller Institute for Basic Research in Science, University of California Berkeley, Aix-Marseille Université, Canadian Institute for Advanced Research, McGill University, Space Telescope Science Institute, NASA Exoplanet Science Institute, Government of Canada, European Commission, Universiteit van Amsterdam, Canada Excellence Research Chairs, Government of Canada, Nederlandse Organisatie voor Wetenschappelijk Onderzoek, University of Toronto, McGill Space Institute, Natural Sciences and Engineering Research Council of Canada, Fonds de recherche du Québec – Nature et technologies, H2020 European Research Council
Awards: G1058115957, Collaborative Research: Mapping the universe in neutral hydrogen with CHIME, Graduate Research Fellowship Program (GRFP), G1897767386, G1908529863, G1979407794, G4133458682, Using fast radio bursts as astrophysical tools, G433322167, G4497416632, Collaborative Research: The Definitive Follow-up Campaign for Fast Radio Bursts, G5180320897, G5433740808, G5539312340, G5622021303, Collaborative Research: The Definitive Follow-up Campaign for Fast Radio Bursts, G58316358, CAREER: Navigating the Environments of the Universe’s Fastest Transients, G6273510985, Collaborative Research: Disentangling the Cosmic Web with Fast Radio Bursts, Collaborative Research: Disentangling the Cosmic Web with Fast Radio Bursts, G807922661, G85701977, G973579988
OpenAlex ID: W7214320554