Light-curve modelling for the initial rising phase of rapidly evolving transients powered by continuous outflow

A wind-driven model is a new framework to observational properties of transients that are powered by continuous outflow from central system. While it has been applied Fast Blue Optical Transients (FBOTs), the applicability limited post-peak behaviours due steady-state assumptions; non-steady-state physics, e.g., expanding outflow, important initial rising phase. In this paper, we construct time-dependent model, which can take into account and time evolution rate. We apply sample well-observed FBOTs. FBOTs require high rates ($\sim 30$ M$_{\odot}$ yr$^{-1}$) fast velocity 0.2-0.3c$), with typical ejecta mass energy budget $\sim 0.2$ 10^{52}$ erg, respectively. The energetic supports idea engine may be related relativistic object, black hole. photospheric temperature $10^{5-6}$ K, suggests will show UV or X-ray flash similar supernova shock breakouts. discuss future prospects surveys follow-up observations in bands. brighter bands than optical bands, timescale bit longer wavelengths. suggest telescopes wide field view play key role discovering characterizing their natures.