The Astrophysical Journal Letters (Jan 2025)

The Massive and Quiescent Elliptical Host Galaxy of the Repeating Fast Radio Burst FRB 20240209A

  • T. Eftekhari,
  • Y. Dong,
  • W. Fong,
  • V. Shah,
  • S. Simha,
  • B. C. Andersen,
  • S. Andrew,
  • M. Bhardwaj,
  • T. Cassanelli,
  • S. Chatterjee,
  • D. A. Coulter,
  • E. Fonseca,
  • B. M. Gaensler,
  • A. C. Gordon,
  • J. W. T. Hessels,
  • A. L. Ibik,
  • R. C. Joseph,
  • L. A. Kahinga,
  • V. Kaspi,
  • B. Kharel,
  • C. D. Kilpatrick,
  • A. E. Lanman,
  • M. Lazda,
  • C. Leung,
  • C. Liu,
  • L. Mas-Ribas,
  • K. W. Masui,
  • R. Mckinven,
  • J. Mena-Parra,
  • A. A. Miller,
  • K. Nimmo,
  • A. Pandhi,
  • S. S. Patil,
  • A. B. Pearlman,
  • Z. Pleunis,
  • J. X. Prochaska,
  • M. Rafiei-Ravandi,
  • M. Sammons,
  • P. Scholz,
  • K. Shin,
  • K. Smith,
  • I. Stairs

DOI
https://doi.org/10.3847/2041-8213/ad9de2
Journal volume & issue
Vol. 979, no. 2
p. L22

Abstract

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The discovery and localization of FRB 20240209A by the Canadian Hydrogen Intensity Mapping Fast Radio Burst (CHIME/FRB) experiment marks the first repeating FRB localized with the CHIME/FRB Outriggers and adds to the small sample of repeating FRBs with associated host galaxies. Here we present Keck and Gemini observations of the host that reveal a redshift z = 0.1384 ± 0.0004. We perform stellar population modeling to jointly fit the optical through mid-IR data of the host and infer a median stellar mass log( M _* / M _⊙ ) = 11.35 ± 0.01 and a mass-weighted stellar population age ~11 Gyr, corresponding to the most massive and oldest FRB host discovered to date. Coupled with a star formation rate <0.31 M _⊙ yr ^−1 , the specific star formation rate <10 ^−11.9 yr ^−1 classifies the host as quiescent. Through surface brightness profile modeling, we determine an elliptical galaxy morphology, marking the host as the first confirmed elliptical FRB host. The discovery of a quiescent early-type host galaxy within a transient class predominantly characterized by late-type star-forming hosts is reminiscent of short-duration gamma-ray bursts, Type Ia supernovae, and ultraluminous X-ray sources. Based on these shared host demographics, coupled with a large offset as demonstrated in our companion Letter, we conclude that preferred sources for FRB 20240209A include magnetars formed through merging binary neutron stars/white dwarfs or the accretion-induced collapse of a white dwarf, or a luminous X-ray binary. Together with FRB 20200120E localized to a globular cluster in M81, our findings provide strong evidence that some fraction of FRBs may arise from a process distinct from the core collapse of massive stars.

Keywords