  High-resolution observations with GRAVITY-VLTI instrument have provided
abundant information about the flares in Sgr A*, the supermassive black hole in
our Galactic center, including the time-dependent location of the centroid (a
"hot spot"), the light curve, and polarization. Yuan et al. (2009) proposed a
"coronal mass ejection" model to explain the flares and their association with
the plasma ejection. The key idea is that magnetic reconnection in the
accretion flow produces the flares and results in the formation and ejection of
flux ropes. The dynamical process proposed in the model has been confirmed by
three-dimensional GRMHD simulations in a later work. Based on this scenario, in
our previous works the radiation of the flux rope has been calculated
analytically and compared to the observations. In the present paper, we develop
the model by directly using numerical simulation data to interpret
observations. We first identify flux ropes formed due to reconnection from the
data. By assuming that electrons are accelerated in the reconnection current
sheet and flow into the flux rope and emit their radiation there, we have
calculated the time-dependent energy distribution of electrons after
phenomenologically considering their injection due to reconnection
acceleration, radiative and adiabatic cooling. The radiation of these electrons
is calculated using the ray-tracing approach. The trajectory of the hot spot,
the radiation light curve during the flare, and the polarization are
calculated. These results are compared with the GRAVITY observations and good
consistencies are found.
