Properties of Type II Plateau Supernova SNLS-04D2dc: Multicolor Light Curves of Shock Breakout and Plateau

TL;DR

This study presents the first successful multicolor light curve modeling of a Type IIP supernova's shock breakout and plateau, confirming theoretical predictions and demonstrating the potential for high-redshift supernova detection.

Contribution

It is the first to reproduce both ultraviolet shock breakout and optical plateau light curves of a Type IIP supernova simultaneously using radiation hydrodynamics.

Findings

Synthetic light curves match observations well.

Shock breakout can be detected at redshifts greater than 1.

Progenitor star estimated to be 20 solar masses with a radius of 800 solar radii.

Abstract

Shock breakout is the brightest radiative phenomenon in a Type II supernova (SN). Although it was predicted to be bright, the direct observation is difficult due to the short duration and X-ray/ultraviolet-peaked spectra. First entire observations of the shock breakouts of Type II Plateau SNe (SNe IIP) were reported in 2008 by ultraviolet and optical observations by the {\it GALEX} satellite and supernova legacy survey (SNLS), named SNLS-04D2dc and SNLS-06D1jd. We present multicolor light curves of a SN IIP, including the shock breakout and plateau, calculated with a multigroup radiation hydrodynamical code {\sc STELLA} and an evolutionary progenitor model. The synthetic multicolor light curves reproduce well the observations of SNLS-04D2dc. This is the first study to reproduce the ultraviolet light curve of the shock breakout and the optical light curve of the plateau consistently. We conclude that SNLS-04D2dc is the explosion with a canonical explosion energy $1.2\times10^{51}$ ergs and that its progenitor is a star with a zero-age main-sequence mass $20M_\odot$ and a presupernova radius $800R_\odot$. The model demonstrates that the peak apparent $B$-band magnitude of the shock breakout would be $m_{\rm B}\sim26.4$ mag if a SN being identical to SNLS-04D2dc occurs at a redshift $z=1$, which can be reached by 8m-class telescopes. The result evidences that the shock breakout has a great potential to detect SNe IIP at $z\gsim1$.