JWST and HST Observations of the Host Galaxy and Supernova SN 2024aihh in EP240801a at z = 1.67
Year: 2026
Type: article
Abstract: We present James Webb Space Telescope (JWST) and Hubble Space Telescope (HST) observations of the counterpart of EP 240801a, at z = 1.67, the first fast X-ray transient (FXT) identified as an X-ray flash by the Einstein Probe and Fermi Gamma-Ray Burst Monitor. Our observations reveal strong photometric and spectroscopic evidence for an associated broad-lined Type Ic supernova (SN) SN 2024aihh, the most distant spectroscopically identified gamma-ray-burst (GRB)–SN to date. The SN exhibits similar luminosity and light-curve evolution to the prototype GRB-SN 1998bw with an absolute magnitude of the SN at ∼23 days rest frame of M F140W ≈ −19 mag. The SN is located in a host galaxy with complex morphology at a large (∼6 kpc) offset in a region of relatively low surface brightness. The region around the SN has a modest star formation rate and is dominated by an intermediate mass-weighted age (1.4 ± 0.3 Gyr) population, despite the apparent presence of a young, massive broad-lined Type Ic SN progenitor. These observations demonstrate that observations with HST and JWST can greatly extend the redshift range over which the GRB/FXT-SN connection can be studied, including in relatively low-luminosity, X-ray-rich events. They demonstrate little apparent evolution in the SN properties from local examples despite EP 240801a originating from an epoch 10 Gyr ago.
Authors: Agnes P.C. van Hoof, Andrew J. Levan, Peter G. Jonker, Morgan Fraser, Luca Izzo, Andrew S. Fruchter, Joyce N. D. van Dalen, Nial R. Tanvir, Jens Hjorth, Antonio Martin-Carrillo, Nikhil Sarin, Laura C. Cotter, Jonathan A. Quirola Vasquez, Maria E. Ravasio, Javi Sánchez-Sierras, Manuel A. P. Torres, Shuai-Qing Jiang, Dong Xu
Institutions: Radboud University Nijmegen, University of Warwick, University College Dublin, Astronomical Observatory of Capodimonte, Space Telescope Science Institute, University of Leicester, University of Copenhagen, University of Cambridge, Universidad de La Laguna, Instituto de Astrofísica de Canarias, Chinese Academy of Sciences, National Astronomical Observatories, University of Chinese Academy of Sciences
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,400
OpenAlex ID: W7119084871