2020/09/29 by MAGIC Collaboration, V. A. Acciari, Stefano Ansoldi +220
Physics and Astronomy · #Astrophysics #Astrophysics and Cosmic Phenomena #Fermi Gamma-ray Space Telescope #Gamma ray #Gamma-ray bursts and supernovae #MAGIC (telescope) #Physics #Power law #Pulsar #Pulsars and Gravitational Waves Research #astro-ph.HE
paper · pdf · doi:10.1051/0004-6361/202039131
published as A&A 643, L14 (2020) · Corresponding authors: Marcos López-Moya, Giovanni Ceribella, Kouichi Hirotani and Thomas Schweizer
openalex publication_date 2020/09/29 · openalex created_date 2020/10/08 · arxiv created 2020/11/20 · arxiv updated 2020/11/23 · openalex updated_date 2026/08/05
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.