Discovery of a Likely Type II Supernova at z = 3.6 with JWST

May 2026 • 2026ApJ..1002...83C

Authors • Coulter, D. A. • Pierel, J. D. R. • DeCoursey, C. • Moriya, T. J. • Siebert, M. R. • Joshi, B. A. • Engesser, M. • Rest, A. • Egami, E. • Shahbandeh, M. • Chen, W. • Fox, O. D. • Strolger, L. G. • Zenati, Y. • Bunker, A. J. • Cargile, P. A. • Curti, M. • Eisenstein, D. J. • Gezari, S. • Gomez, S. • Guolo, M. • Hainline, K. • Jencson, J. • Johnson, B. D. • Karmen, M. • Maiolino, R. • Quimby, R. M. • Rinaldi, P. • Robertson, B. • Tacchella, S. • Sun, F. • Wang, Q. • Wevers, T.

Abstract • Transient astronomy of the early, high-redshift (z > 3) Universe is an unexplored regime that offers the possibility of probing the first stars and the epoch of reionization. During Cycles 1 and 2 of the James Webb Space Telescope (JWST), the JWST Advanced Deep Extragalactic Survey program enabled one of the first searches for transients in deep images (∼30 AB mag) over a relatively wide area (25 arcmin²). One transient, AT 2023adsv, was discovered with an F200W magnitude of 28.04 AB mag, and subsequent JWST observations revealed that the transient is a likely supernova (SN) in a host with z_spec = 3.613 ± 0.001 and an inferred metallicity at the position of the SN of Z_* = 0.3 ± 0.1 Z_⊙. At this redshift, the first detections in F115W and F150W show that AT 2023adsv had bright rest-frame UV flux at the time of discovery. The multiband light curve of AT 2023adsv is best matched by a template of a Type IIP SN (SN IIP) with a peak absolute magnitude of M_B ≍ −18.3 AB mag. We find a good match to a 20 M_⊙ red supergiant progenitor star with an explosion energy of 2 × 10⁵¹ erg, likely higher than normally observed in the local Universe, but consistent with SNe IIP drawn from local, lower-metallicity environments. AT 2023adsv is the most distant photometrically classified SN IIP yet discovered with a spectroscopic redshift measurement, and may represent a global shift in SN IIP properties as a function of redshift.

Links

• ELECTR https://doi.org/10.3847/1538-4357/ae595d
• PREPRINT http://arxiv.org/abs/2501.05513