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

Journal article

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 zspec = 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 MB ≈ −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.

Authors: Coulter, DA; Pierel, JDR; DeCoursey, C; Moriya, TJ; Siebert, MR

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: American Astronomical Society
• Journal: The Astrophysical Journal
• Volume: 1002
• Issue: 1
• Pages: 83
• Article number: 83
• Publication date: 2026-04-28
• Acceptance date: 2026-03-26
• DOI: 10.3847/1538-4357/ae595d
• EISSN: 1538-4357
• ISSN: 0004637X, 0004-637X
• Language: English
• Keywords: Metallicity; Core-collapse supernovae; Type II supernovae; High-redshift galaxies; Supernovae