Shock Breakout in Dense Circumstellar Material with Application to PS1-13arp

TL;DR

This paper investigates how dense circumstellar material affects supernova shock breakout signals, using models and a specific supernova case, suggesting SBO detection may be more feasible than previously thought.

Contribution

It provides combined analytic and numerical models of SBO in dense CSM and applies these to PS1-13arp, offering new insights into SBO observability in Type II supernovae.

Findings

PS1-13arp's SBO consistent with a wind of ~0.08 M_sun and ~1900 R_sun

Dense CSM can lengthen SBO duration and increase luminosity

Future SBO detections in SNe II may be more accessible

Abstract

Shock breakout (SBO), the first expected electromagnetic signature of a supernova (SN), can be an important probe of the progenitors of these explosions. Unfortunately, SBO is difficult to capture with current surveys due to its brief timescale ($\lesssim 1\,$hr). However, SBO may be lengthened when dense circumstellar material (CSM) is present. Indeed, recent photometric modeling studies of SNe, as well as early spectroscopy, suggest that such dense CSM may be present more often than previously expected. If true, this should also affect the features of SBO. We present an exploration of the impact of such CSM interaction on the SBO width and luminosity using both analytic and numerical modeling, where we parameterize the CSM as a steady-state wind. We then compare this modeling to PS1-13arp, a SN that showed an early UV excess that has been argued to be SBO in dense CSM. We find PS1-13arp is well fit with a wind of mass $\sim 0.08\, M_{\odot}$ and radius $\sim 1900\, R_{\odot}$, parameters which are similar to, if not slightly less massive than, what have been inferred for Type II SNe using photometric modeling. This similarity suggests that future SBO observations of SNe~II may be easier to obtain than previously appreciated.