Author:
Aliu E.,Anderhub H.,Antonelli L. A.,Antoranz P.,Backes M.,Baixeras C.,Barrio J. A.,Bartko H.,Bastieri D.,Becker J. K.,Bednarek W.,Berger K.,Bernardini E.,Bigongiari C.,Biland A.,Bock R. K.,Bonnoli G.,Bordas P.,Bosch-Ramon V.,Bretz T.,Britvitch I.,Camara M.,Carmona E.,Chilingarian A.,Commichau S.,Contreras J. L.,Cortina J.,Costado M. T.,Covino S.,Curtef V.,Dazzi F.,De Angelis A.,De Cea del Pozo E.,de los Reyes R.,De Lotto B.,De Maria M.,De Sabata F.,Delgado Mendez C.,Dominguez A.,Dorner D.,Doro M.,Elsässer D.,Errando M.,Fagiolini M.,Ferenc D.,Fernandez E.,Firpo R.,Fonseca M. V.,Font L.,Galante N.,Garcia Lopez R. J.,Garczarczyk M.,Gaug M.,Goebel F.,Hadasch D.,Hayashida M.,Herrero A.,Höhne D.,Hose J.,Hsu C. C.,Huber S.,Jogler T.,Kranich D.,La Barbera A.,Laille A.,Leonardo E.,Lindfors E.,Lombardi S.,Longo F.,Lopez M.,Lorenz E.,Majumdar P.,Maneva G.,Mankuzhiyil N.,Mannheim K.,Maraschi L.,Mariotti M.,Martinez M.,Mazin D.,Meucci M.,Meyer M.,Miranda J. M.,Mirzoyan R.,Moles M.,Moralejo A.,Nieto D.,Nilsson K.,Ninkovic J.,Otte N.,Oya I.,Paoletti R.,Paredes J. M.,Pasanen M.,Pascoli D.,Pauss F.,Pegna R. G.,Perez-Torres M. A.,Persic M.,Peruzzo L.,Piccioli A.,Prada F.,Prandini E.,Puchades N.,Raymers A.,Rhode W.,Ribó M.,Rico J.,Rissi M.,Robert A.,Rügamer S.,Saggion A.,Saito T. Y.,Salvati M.,Sanchez-Conde M.,Sartori P.,Satalecka K.,Scalzotto V.,Scapin V.,Schweizer T.,Shayduk M.,Shinozaki K.,Shore S. N.,Sidro N.,Sierpowska-Bartosik A.,Sillanpää A.,Sobczynska D.,Spanier F.,Stamerra A.,Stark L. S.,Takalo L.,Tavecchio F.,Temnikov P.,Tescaro D.,Teshima M.,Tluczykont M.,Torres D. F.,Turini N.,Vankov H.,Venturini A.,Vitale V.,Wagner R. M.,Wittek W.,Zabalza V.,Zandanel F.,Zanin R.,Zapatero J.,de Jager O.C.,de Ona Wilhelmi E.
Abstract
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 γ-ray Imaging Cherenkov (MAGIC) telescope to 25 giga–electron volts. In this configuration, we detected pulsed γ-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.