ar X iv : a st ro - p h / 06 10 92 5 v 1 3 1 O ct 2 00 6 Discovery of microquasar LS I + 61 303 at VHE gamma - rays with MAGIC

Here we report the discovery of very high energy (> 100GeV) γ-ray emission from the radio emitting X-ray binary LS I +61 303 with the Major Atmospheric Gamma Imaging Cherenkov (MAGIC) telescope. This high energy emission has been found to be variable, detected 4 days after the periastron passage and lasting for several days. The data have been taken along different orbital cycles, and the fact that the detections occur at similar orbital phases, suggests that the emission is periodic. Two different scenarios have been involved to explain this high energy emission: the microquasar scenario where the γ-rays are produced in a radio-emitting jet; or the pulsar binary scenario, where they are produced in the shock which is generated by the interaction of a pulsar wind and the wind of the massive companion.