Matt Kistler homepage.  Matthew Kistler  TeV Gamma Rays From Geminga and the Origin of the GeV Positron Excess

Milagro, an all-sky gamma-ray telescope, has measured TeV emission from a number of positions in the northern sky.  One of the most intriguing surrounds the aged gamma-ray pulsar Geminga, where the emission surprisingly arises from an extended region.  Along with Hasan Yuksel and Todor Stanev, we found that this reveals the existence of an ancient, powerful cosmic-ray accelerator that also can plausibly account for the multi-GeV positron excess that has evaded explanation.  We explored a number of testable predictions for gamma-ray, electron/positron, and neutrino experiments that can confirm the first direct detection of a cosmic-ray source.