2-$\sigma$ contours for a subset of IceCube events associated with the inner Galaxy as determined from 2D Gaussian statistics and the median angular errors and positions given by [@Aartsen14a]. Two PeV events (14, “Bert") and 35 (“Big Bird") as well as three sub-PeV (2, 15, 25) events are within 2-$\sigma$ from . []{data-label="fig:Galactic"}](f6.pdf){width="280pt"}

Discussion
==========

Explaining the origin of the recently detected PeV neutrinos by IceCube is a fundamental challenge for models of particle acceleration. The observations imply a source that can produce substantial fluxes of protons with energies considerably higher than those expected from isolated SNRs. Since isolated SNRs remain the most likely source of CRs below a few PeV, the neutrino source must produce high-energy protons without conflicting with the observed properties of galactic CRs. The underlying protons producing the neutrinos in the CSF model described above have a hard spectrum, and are few in number, avoiding any conflict with low-energy CR population measurements. The CSFs may contribute to the high-energy end of the CR population produced by isolated SNRs and superbubbles [see e.g. @binns_SB07] and, we believe the strong plasma flows in compact clusters of young stars, such as , contain the energy and specific properties needed 