  We report the discovery of a small Halpha nebula positionally coincident with
the candidate neutron star AX J0851.9-4617.4 located at the center of the
supernova remnant G 266.1-1.2. The nebula has a roughly circular shape with a
diameter of ~6'' and a flux of ~10^-2 photons cm^-2 s^-1 in the Halpha line.
Considering the uncertainties in the distance and energy output from the
putative neutron star, we find that such a flux can be explained either in a
bow-shock model or assuming that the nebular emission is due to
photo-ionization and heating of the ambient gas.
