The GALEX-PTF Experiment. II. Supernova Progenitor Radius and Energetics via Shock-cooling Modeling

Abstract The radius and surface composition of an exploding massive star, as well the explosion energy per unit mass, can be measured using early ultraviolet (UV) observations core-collapse supernovae (CC SNe). We present results from a simultaneous Galaxy Evolution Explorer (GALEX) Palomar Transient Factory (PTF) search for UV emission SNe. analyze five CC SNe which we obtained near-UV (NUV) measurements before first ground-based R -band detection. introduce SOPRANOS, new maximum likelihood fitting tool models with variable temporal validity windows, use it to fit Sapir & Waxman shock-cooling model data. report four Type II progenitor radii in range * ≈ 600–1100 ⊙ shock velocity parameter v s 2700–6000 km −1 ( E / M 2–8 × 10 50 erg/ ) one IIb SN 210 11,000 1.8 51 ). Our pilot GALEX/PTF project thus suggests that dedicated, systematic survey NUV band, such wide-field explorer ULTRASAT mission, is compelling method study properties progenitors energetics.