  We perform radiative transfer simulations for kilonova in various situations,
including the cases of prompt collapse to a black hole from neutron-star
mergers, high-velocity ejecta possibly accelerated by magnetars, and a black
hole-neutron star merger. Our calculations are done employing ejecta profiles
predicted by numerical-relativity simulations and a new line list for all the
r-process elements. We found that (i) the optical emission for binary neutron
stars promptly collapsing to a black hole would be fainter by
$\gtrsim1$-$2\,{\rm mag}$ than that found in GW170817, while the infrared
emission could be as bright as that in GW170817 if the post-merger ejecta is as
massive as $\approx0.01\,M_\odot$; (ii) the kilonova would be brighter than
that observed in GW170817 for the case that the ejecta is highly accelerated by
the electromagnetic energy injection from the remnant, but it would decline
rapidly and the magnitude would become fainter than in GW170817 within a few
days; (iii) the optical emission from a black hole-neutron star merger ejecta
could be as bright as that observed in GW170817 for the case that sufficiently
large amount of matter is ejected ($\gtrsim0.02\,M_\odot$), while the infrared
brightness would be brighter by $1$-$2\,{\rm mag}$ at the same time. We show
that the difference in the ejecta properties would be imprinted in the
differences in the peak brightness and time of peak. This indicates that we may
be able to infer the type of the central engine for kilonovae by observation of
the peak in the multiple band.

High Energy Astrophysical Phenomena