  We investigate the evolution of the afterglow produced by the deceleration of
the non-relativistic material due to its surroundings. The ejecta mass is
launched into the circumstellar medium with equivalent kinetic energy expressed
as a power-law velocity distribution $E\propto (\Gamma\beta)^{-\alpha}$. The
density profile of this medium follows a power law $n(r)\propto r^{-k}$ with
$k$ the stratification parameter, which accounts for the usual cases of a
constant medium ($k=0$) and a wind-like medium ($k=2$). A long-lasting central
engine, which injects energy into the ejected material as ($E\propto t^{1-q}$)
was also assumed. With our model, we show the predicted light curves associated
with this emission for different sets of initial conditions and notice the
effect of the variation of these parameters on the frequencies, timescales and
intensities. The results are discussed in the Kilonova scenario.
