Observation of pulsed gamma-rays above 25 GeV from the Crab Pulsar with MAGIC

The MAGIC Collaboration.

J. M. Paredes investigador correspondiente del IAR.

Resumen: One fundamental question about pulsars concerns the mechanism of their pulsed electromagnetic emission. Measuring the high-end region of a pulsar's spectrum would shed light on this question. By developing a new electronic trigger, we lowered the threshold of the Major Atmospheric gamma-ray Imaging Cherenkov (MAGIC) telescope to 25 giga—electron volts. In this configuration, we detected pulsed gamma-rays from the Crab pulsar that were greater than 25 giga—electron volts, revealing a relatively high cutoff energy in the phase-averaged spectrum. This indicates that the emission occurs far out in the magnetosphere, hence excluding the polar-cap scenario as a possible explanation of our measurement. The high cutoff energy also challenges the slot-gap scenario.