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 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 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 \times 10 ^ { 51 } ergs and that its progenitor is a star with a zero-age main-sequence mass 20 M _ { \odot } and a presupernova radius 800 R _ { \odot } .
The model demonstrates that the peak apparent B -band magnitude of the shock breakout would be m _ { B } \sim 26.4 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 \mathrel { \hbox to 0.0 pt { \lower 4.0 pt \hbox { $ \sim$ } } \raise 1.0 pt \hbox { $ > $ } } 1 .