RT Journal Article T1 Search for VHE gamma-ray emission from Geminga pulsar and nebula with the MAGIC telescopes A1 Antoranz Canales, Pedro A1 Barrio Uña, Juan Abel A1 Bonnefoy, Simon Francois Albert A1 Contreras González, José Luis A1 Fonseca González, María Victoria A1 López Moya, Marcos A1 Miranda Pantoja, José Miguel A1 Nievas Rosillo, Mireia AB The Geminga pulsar, one of the brighest gamma-ray sources, is a promising candidate for emission of very-high-energy (VHE > 100 GeV) pulsed gamma rays. Also, detection of a large nebula have been claimed by water Cherenkov instruments. We performed deep observations of Geminga with the MAGIC telescopes, yielding 63 hours of good-quality data, and searched for emission from the pulsar and pulsar wind nebula. We did not find any significant detection, and derived 95% confidence level upper limits. The resulting upper limits of 5.3 × 10^(−13) TeV cm^(−2)s^(−1) for the Geminga pulsar and 3.5 × 10^(−12) TeV cm^(−2)s^(−1) for the surrounding nebula at 50 GeV are the most constraining ones obtained so far at VHE. To complement the VHE observations, we also analyzed 5 years of Fermi-LAT data from Geminga, finding that the sub-exponential cut-off is preferred over the exponential cut-off that has been typically used in the literature. We also find that, above 10 GeV, the gamma-ray spectra from Geminga can be described with a power law with index softer than 5. The extrapolation of the power-law Fermi-LAT pulsed spectra to VHE goes well below the MAGIC upper limits, indicating that the detection of pulsed emission from Geminga with the current generation of Cherenkov telescopes is very difficult. PB EDP Sciencies SN 1432-0746 YR 2016 FD 2016-07 LK https://hdl.handle.net/20.500.14352/24632 UL https://hdl.handle.net/20.500.14352/24632 LA eng NO © ESO, 2016. Artículo firmado por 155 autores. We would like to thank the Instituto de Astrofísica de Canarias for the excellent working conditions at the Observatorio del Roque de los Muchachos in La Palma. The financial support of the German BMBF and MPG, the Italian INFN and INAF, the Swiss National Fund SNF, the ERDF under the Spanish MINECO (FPA2012-39502), and the Japanese JSPS and MEXT is gratefully acknowledged. This work was also supported by the Centro de Excelencia Severo Ochoa SEV-2012- 0234, CPAN CSD2007-00042, and MultiDark CSD2009-00064 projects of the Spanish Consolider-Ingenio 2010 programme, by grant 268740 of the Academy of Finland, by the Croatian Science Foundation (HrZZ) Project 09/176 and the University of Rijeka Project 13.12.1.3.02, by the DFG Collaborative Research Centers SFB823/C4 and SFB876/C3, and by the Polish MNiSzW grant 745/N-HESS-MAGIC/2010/0. NO Ministerio de Economía y Competitividad (MINECO) NO German BMBF and MPG NO Italian INFN and INAF NO Swiss National Fund SNF NO Japanese JSPS and MEXT NO Centro de Excelencia Severo Ochoa NO Spanish Consolider-Ingenio 2010 programme NO Academy of Finland NO Croatian Science Foundation (HrZZ) NO University of Rijeka NO DFG Collaborative Research Centers NO Polish MNiSzW DS Docta Complutense RD 18 abr 2025