Light-curve Analysis of the Classical Nova YZ Ret: Revisiting with Fully Self-consistent Nova Outburst Models

YZ Ret is a well-observed nova from the first detection of an X-ray flash phase in classical novae until the end of a supersoft X-ray source phase. We have reanalyzed multiwavelength light curves of YZ Ret over the total duration of the outburst. Our fully self-consistent nova outburst model, a 1.25 M ⊙ white dwarf (WD) with a mass accretion rate of 1 × 10 −9 M ⊙ yr −1 on to the WD, reasonably reproduced V / g light curves as well as the very early X-ray flash and late supersoft X-ray light curves. This model explains the emergence epoch of the GeV gamma-ray emission because a shock naturally arises far outside the nova (WD) photosphere just after the optical maximum. In our model, before optical maximum, later ejected matter has a smaller velocity than that of earlier ejecta, and therefore, the ejecta expands while, after optical maximum, later ejected matter has a larger velocity than that of earlier ejecta, and the collision with the earlier ejecta makes a shock.