A spatially resolved view of Fast Radio Burst host metallicities with Integral-field Spectroscopy
Year: 2026
Type: preprint
Abstract: Magnetar sources are the leading theory for Fast Radio Burst (FRB) progenitors. If magnetars are indeed the dominant sources, we may thus expect any metallicity preference for magnetar formation to be reflected in the FRB site in host galaxies. Here, we leverage Integral Field Unit (IFU) spectroscopy to spatially resolve gas-phase metallicity distribution in five FRB host galaxies: FRB 20240210A, FRB 20240312D, FRB 20250227A, FRB 20211127I, and FRB 20250316A, at $z < 0.05$, including the FRB site, with the O3N2 index. We observed the first four sources with the newly commissioned Large Lenslet Array Magellan Spectrograph (LLAMAS) IFU on the Magellan Telescopes and used archival Keck/KCWI data for FRB 20250316A. We find ISM metallicity variations of at least 0.3 dex within individual hosts for the majority of the sample, with median values spanning $12 + log(O/H) \approx$ 8.5--8.7. At the burst sites, four have metallicities of $12 + \log(O/H) \approx 8.5$--8.9, while the fifth has a metallicity below 8.5. These findings reveal substantial metallicity variations both among FRB host galaxies and within the local environments of the bursts. Consequently, our study shows that longslit-based global estimates of host galaxy metallicity do not always represent the true burst-site distributions. We therefore advocate for IFU follow-up of larger host samples to ultimately provide FRB-site-relevant observational constraints on metallicity preferences for FRB occurrence.
Source: arXiv (Cornell University)
Authors: Simha, Sunil, Chen, Hsiao-Wen, Fong, Wen-fai, Hughes, Sarah, Dong, Yuxin, Prochaska, J. Xavier, Tejos, Nicolas, Eftekhari, Tarraneh, Gordon, Alexa C., Ryder, Stuart D., Sammons, Mawson W., Curtin, Alice P., Kaspi, Victoria M., Lanman, Adam E., Leung, Calvin, Masui, Kiyoshi W., Pearlman, Aaron B., Shannon, Ryan M.
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, Brinson Foundation, Research Corporation for Science Advancement, Northwestern University, 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, Government of Canada, 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: Collaborative Research: Mapping the universe in neutral hydrogen with CHIME, Graduate Research Fellowship Program (GRFP), G1897767386, G3352712625, G433322167, Collaborative Research: The Definitive Follow-up Campaign for Fast Radio Bursts, 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, G85701977
OpenAlex ID: W7220909052