SN 2025dys: A luminous supernova explosion from a partially stripped helium star
We present well-sampled multi-band imaging and low- to medium-resolution spectroscopic observations of the early-discovered Type~II supernova (SN)~2025dys. The photometric evolution exhibits a rise time of $\sim$\,18 days ($r$ band) and a rapid decline transitioning to the radioactive decay tail at $\sim$\,70 days. SN~...