GRB off-axis afterglows and the emission from the accompanying
  supernovae
  Gamma-ray burst (GRB) afterglows are likely produced in the shock that is
driven as the GRB jet interacts with the external medium. Long-duration GRBs
are also associated with powerful supernovae (SNe). We consider the optical and
radio afterglows of long GRBs for both blasts viewed along the jet axis
("on-axis" afterglows) and misaligned observes ("off-axis" afterglows).
Comparing the optical emission from the afterglow with that of the accompanying
SN, using SN 1998bw as an archetype, we find that only a few percent of
afterglows viewed off-axis are brighter than the SN. For observable optical
off-axis afterglows, the viewing angle is at most twice the half-opening angle
of the GRB jet. Radio off-axis afterglows should be detected with upcoming
radio surveys within a few hundred Mpc. We propose that these surveys will act
as "radio triggers", and that dedicated radio facilities should follow-up these
sources. Follow-ups can unveil the presence of the radio SN remnant, if
present. In addition, they can probe the presence of a mildly relativistic
component, either associated with the GRB jet or the SN ejecta, expected in
these sources.
