2024/07/02 by Itsuki Yamanaka, Yamanaka, Itsuki, Bunyo Hatsukade +13
Physics and Astronomy · #Astrophysics and Star Formation Studies #Astrophysics of Galaxies (astro-ph.GA) #Cosmology and Gravitation Theories #FOS: Physical sciences #Galaxies: Formation, Evolution, Phenomena
paper · pdf · doi:10.48550/arxiv.2407.01889
openalex publication_date 2024/07/02 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/01
We report the detection of the CO(2-1) emission line with a spatial resolution of 0.9 arcsec (3.5 kpc) from the host galaxy of the fast radio burst (FRB), FRB 20191001A at z=0.2340, using the Atacama Large Millimeter/submillimeter Array. This is the first detection of spatially resolved CO emission from the host galaxy of an FRB at a cosmological distance. The inferred molecular gas mass of the host galaxy is (2.3±0.4)×1010 M_\odot, indicating that it is gas-rich, as evidenced by the measured molecular gas fraction μgas=0.50±0.22. This molecular-gas mass and the star formation rate of the host, SFR=8.06±2.42 \mathrmM_\odot yr-1, differ from those observed in the other FRB host galaxies with the average Mgas=9.6×108 M_\odot and SFR=0.90 \mathrmM_\odot yr-1. This lends further credibility to the hypothesis that FRBs may originate from single or multiple progenitors across a diverse range of galaxy environments. Based on the observed velocity field modeling, we find that the molecular gas disk is dominated by an ordered circular rotation, despite the fact that the host galaxy has a gas-rich companion galaxy with a projected separation of ∼ 25 kpc. The formation of the FRB's progenitor might not have been triggered by this interaction. We derive the 3σ upper limit of the molecular gas column density at the FRB detection site to be < 2.1× 1021 \mathrmcm-2 with a 3σ upper limit.