  It is generally held that >100 TeV emission from astrophysical objects
unambiguously demonstrates the presence of PeV protons or nuclei, due to the
unavoidable Klein-Nishina suppression of inverse Compton emission from
electrons. However, in the presence of inverse Compton dominated cooling, hard
high-energy electron spectra are possible. We show that the environmental
requirements for such spectra can naturally be met in spiral arms, and in
particular in regions of enhanced star formation activity, the natural
locations for the most promising electron accelerators: powerful young pulsars.
Our scenario suggests a population of hard ultra-high energy sources is likely
to be revealed in future searches, and may also provide a natural explanation
for the 100 TeV sources recently reported by HAWC.
