HAWC Observations Strongly Favor Pulsar Interpretations of the
  Cosmic-Ray Positron Excess
  Recent measurements of the Geminga and B0656+14 pulsars by the gamma-ray
telescope HAWC (along with earlier measurements by Milagro) indicate that these
objects generate significant fluxes of very high-energy electrons. In this
paper, we use the very high-energy gamma-ray intensity and spectrum of these
pulsars to calculate and constrain their expected contributions to the local
cosmic-ray positron spectrum. Among models that are capable of reproducing the
observed characteristics of the gamma-ray emission, we find that pulsars
invariably produce a flux of high-energy positrons that is similar in spectrum
and magnitude to the positron fraction measured by PAMELA and AMS-02. In light
of this result, we conclude that it is very likely that pulsars provide the
dominant contribution to the long perplexing cosmic-ray positron excess.
