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Asano, K.; Babić, A.; Baquero, A.; Becerra González, J.; Bellizzi, L.; Bernardos, M.; Berti, A.; Besenrieder, J.; Bhattacharyya, W.; Bigongiari, C.; Bonnoli, G.; Bošnjak, Ž.; Carosi, R.; Cerruti, M.; Chai, Y.; Cikota, S.; Colombo, E.; Contreras, J. L.; D’Elia, V.; De Angelis, A.; Delfino, M.; Delgado, J.; Di Girolamo, T.; Di Pierro, F.; Di Venere, L.; Do Souto Espiñeira, E.; Dominis Prester, D.; Dorner, D.; Fattorini, A.; Ferrara, G.; Foffano, L.; Font, L.; Fukami, S.; Garczarczyk, M.; Gliwny, P.; Godinović, N.; Hadasch, D.; Heckmann, L.; Hrupec, D.; Hütten, M.; Inada, T.; Inoue, S.; Ishio, K.; Iwamura, Y.; Jormanainen, J.; Jouvin, L.; Karjalainen, M.; Kobayashi, Y.; Kubo, H.; Kushida, J.; Longo, F.; López-Coto, R.; López-Oramas, A.; Loporchio, S.; Maggio, C.; Mallamaci, M.; Mannheim, K.; Maraschi, L.; Mariotti, M.; Mender, S.; Miceli, D.; Miener, T.; Minev, M.; Mirzoyan, R.; Moretti, E.; Munar-Adrover, P.; Neustroev, V.; Nishijima, K.; Nozaki, S.; Ohtani, Y.; Palatiello, M.; Paneque, D.; Peñil, P.; Persic, M.; Priyadarshi, C.; Puljak, I.; Ribó, M.; Righi, C.; Rugliancich, A.; Saha, L.; Satalecka, K.; Saturni, F. G.; Schleicher, B.; Schweizer, T.; Sitarek, J.; Šnidarić, I.; Spolon, A.; Strzys, M.; Surić, T.; Tavecchio, F.; Tosti, L.; Tutone, A.; van Scherpenberg, J.; Vanzo, G.; Vazquez Acosta, M.; Vigorito, C. F.; Vitale, V.; Vovk, I.; Hirotani, K.; Saz Parkinson, P. M.
Astronomy and astrophysics (Berlin), 11/2020, Letnik: 643Journal Article
We report the detection of pulsed gamma-ray emission from the Geminga pulsar (PSR J0633+1746) between 15 GeV and 75 GeV. This is the first time a middle-aged pulsar has been detected up to these energies. Observations were carried out with the MAGIC telescopes between 2017 and 2019 using the low-energy threshold Sum-Trigger-II system. After quality selection cuts, ∼80 h of observational data were used for this analysis. To compare with the emission at lower energies below the sensitivity range of MAGIC, 11 years of Fermi -LAT data above 100 MeV were also analysed. From the two pulses per rotation seen by Fermi -LAT, only the second one, P 2, is detected in the MAGIC energy range, with a significance of 6.3 σ . The spectrum measured by MAGIC is well-represented by a simple power law of spectral index Γ = 5.62 ± 0.54, which smoothly extends the Fermi -LAT spectrum. A joint fit to MAGIC and Fermi -LAT data rules out the existence of a sub-exponential cut-off in the combined energy range at the 3.6 σ significance level. The power-law tail emission detected by MAGIC is interpreted as the transition from curvature radiation to Inverse Compton Scattering of particles accelerated in the northern outer gap.
