The Milagro anti – Center hot spots : cosmic rays from the Geminga Supernova ? ( Research Note )

Context. The Milagro experiment has announced the discovery of an excess flux of TeV cosmic rays from the general direction of the heliotail, also close to the Galactic anti–Center. Aims. We investigate the hypothesis that the excess cosmic rays were produced in the SN explosion which gave birth to the Geminga pulsar. Methods. The assumptions underlying our proposed scenario are that the Geminga Supernova occurred about 3.4 10 5 years ago (as indicated by the spin down timescale); that a burst of cosmic rays was injected with total energy ∼ 10 49 erg (i.e., about 1% of a typical SN output); that the cosmic rays have since diffused according to the Bohm prescription (i.e., with a diffusion coefficient of the order of c × r L , with c the speed of light and r L the Larmor radius); and that the Geminga pulsar was born with a positive radial velocity of at least 160 km s −1. Results. We find that our hypothesis is consistent with the available information. The assumption about the velocity of the Geminga pulsar was already proposed by previous investigators in connection with the formation of the Local Bubble. Conclusions. If the observed cosmic ray excess does indeed arise from the Geminga SN explosion, the long sought " smoking gun " connecting cosmic rays with Supernovae would finally be at hand. It could be said that while looking for the " smoking gun " we were hit by the bullets themselves.