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

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 \(z\gsim1\).