Supernova PTF 09uj: A possible shock breakout from a dense circumstellar wind

TL;DR

This paper reports the discovery and analysis of a Type IIn supernova, PTF 09uj, highlighting a rapid UV light curve rise due to shock breakout in dense circumstellar material, revealing recent high mass-loss from the progenitor.

Contribution

It provides the first detailed observation of a supernova shock breakout in dense CSM, linking UV light curve features to progenitor mass-loss history.

Findings

Fast UV light curve rise indicates shock breakout in dense CSM

Progenitor experienced high mass-loss rate (~0.1 solar masses/year) before explosion

The supernova had a rapid decay rate compared to other Type IIn SNe

Abstract

Type-IIn supernovae (SNe), which are characterized by strong interaction of their ejecta with the surrounding circumstellar matter (CSM), provide a unique opportunity to study the mass-loss history of massive stars shortly before their explosive death. We present the discovery and follow-up observations of a Type IIn SN, PTF 09uj, detected by the Palomar Transient Factory (PTF). Serendipitous observations by GALEX at ultraviolet (UV) wavelengths detected the rise of the SN light curve prior to the PTF discovery. The UV light curve of the SN rose fast, with a time scale of a few days, to a UV absolute AB magnitude of about -19.5. Modeling our observations, we suggest that the fast rise of the UV light curve is due to the breakout of the SN shock through the dense CSM (n~10^10 cm^-3). Furthermore, we find that prior to the explosion the progenitor went through a phase of high mass-loss rate (~0.1 solar mass per year) that lasted for a few years. The decay rate of this SN was fast relative to that of other SNe IIn.