AstroNote 2025-285

We report the detection of a possible Type II Supernova in the JWST NIRCam imaging of the galaxy cluster WHL0137-08. (GO 2282, PI: Coe Dan). The supernova was discovered in the data from the JWST GO 2282 program. The coordinates of the transient are RA = 01:37:23.390 and Dec = −08:28:38.17 (J2000). We perform preliminary photometry for the JWST NIRCam imaging. For the first epoch (MJD 59790), we obtained F090W, F115W, F150W, F200W, F277W, F356W, F410M and F444W magnitudes of 28.50 ± 0.35 AB, 27.09 ± 0.11 AB, 27.08 ± 0.10 AB, 26.73 ± 0.07 AB, 27.61 ± 0.23 AB, 28.34 ± 0.52 AB, 28.18 ±0.78 and >28.41 AB, respectively. For the second epoch (MJD 59954), we obtained F090W, F115W, F277W and F356W magnitudes of 28.77 ± 0.53 AB, 28.63 ± 0.34 AB, 27.87 ± 0.30 AB and 27.88 ± 0.29 AB, respectively. The supernova is no longer detected in the data from the VENUS program (GO 6882, PI: Fujimoto Seiji).
Using SNCosmo to fit several SN models to our photometry, the best match indicates a Type II supernova. The host galaxy's photometric redshift, determined by EAZY, is z = 2.0 ± 0.3.