Ionizing stellar population in the disc of NGC 3310 - II. The Wolf-Rayet
  population
  We use integral field spectroscopy to study in detail the Wolf-Rayet (WR)
population in NGC 3310, spatially resolving 18 star-forming knots with typical
sizes of 200-300 pc in the disc of the galaxy hosting a substantial population
of WRs. The detected emission in the so-called blue bump is attributed mainly
to late-type nitrogen WRs (WNL), ranging from a few dozens to several hundreds
of stars per region. Our estimated WNL/(WNL+O) ratio is comparable to reported
empirical relations once the extinction-corrected emission is further corrected
by the presence of dust grains inside the nebula that absorb a non-negligible
fraction of UV photons. Comparisons of observables with stellar population
models show disagreement by factors larger than 2-3. However, if the effects of
interacting binaries and/or photon leakage are taken into account, observations
and predictions tend to converge. We estimate the binary fraction of the \hii
regions hosting WRs to be significant in order to recover the observed X-ray
flux, hence proving that the binary channel can be critical when predicting
observables. We also explore the connection of the environment with the current
hypothesis that WRs can be progenitors to long-duration gamma-ray bursts
(GRBs). Galaxy interactions, which can trigger strong episodes of star
formation in the central regions, may be a plausible environment where WRs may
act as progenitors of GRBs. Finally, even though the chemical abundance is
generally homogeneous, we also find weak evidence for rapid N pollution by WR
stellar winds at scales of ~ 200 pc.
