Acciari, V. A.; Ansoldi, S.; Antonelli, L. A.; Arbet Engels, A.; Baack, D.; Babić, A.; Banerjee, B.; Barres de Almeida, U.; Barrio, J. A.; Becerra González, J.; Bednarek, W.; Bellizzi, L.; Bernardini, E.; Berti, A.; Besenrieder, J.; Bhattacharyya, W.; Bigongiari, C.; Biland, A.; Blanch, O.; Bonnoli, G.; Bošnjak, Ž.; Busetto, G.; Carosi, R.; Ceribella, G.; Chai, Y.; Chilingaryan, A.; Cikota, S.; Colak, S. M.; Colin, U.; Colombo, E.; Contreras, J. L.; Cortina, J.; Covino, S.; D’Elia, V.; Da Vela, P.; Dazzi, F.; De Angelis, A.; De Lotto, B.; Delfino, M.; Delgado, J.; Depaoli, D.; Di Pierro, F.; Di Venere, L.; Do Souto Espiñeira, E.; Dominis Prester, D.; Donini, A.; Dorner, D.; Doro, M.; Elsaesser, D.; Fallah Ramazani, V.; Fattorini, A.; Ferrara, G.; Fidalgo, D.; Foffano, L.; Fonseca, M. V.; Font, L.; Fruck, C.; Fukami, S.; García López, R. J.; Garczarczyk, M.; Gasparyan, S.; Gaug, M.; Giglietto, N.; Giordano, F.; Godinović, N.; Green, D.; Guberman, D.; Hadasch, D.; Hahn, A.; Herrera, J.; Hoang, J.; Hrupec, D.; Hütten, M.; Inada, T.; Inoue, S.; Ishio, K.; Iwamura, Y.; Jouvin, L.; Kerszberg, D.; Kubo, H.; Kushida, J.; Lamastra, A.; Lelas, D.; Leone, F.; Lindfors, E.; Lombardi, S.; Longo, F.; López, M.; López-Coto, R.; López-Oramas, A.; Loporchio, S.; Machado de Oliveira Fraga, B.; Maggio, C.; Majumdar, P.; Makariev, M.; Mallamaci, M.; Maneva, G.; Manganaro, M.; Mannheim, K.; Maraschi, L. et al.
Bibliographical reference
The Astrophysical Journal
Advertised on:
10
2019
Journal
Citations
45
Refereed citations
33
Description
Starburst galaxies and star-forming active galactic nuclei are among the candidate sources thought to contribute appreciably to the extragalactic gamma-ray and neutrino backgrounds. NGC 1068 is the brightest of the star-forming galaxies found to emit gamma-rays from 0.1 to 50 GeV. Precise measurements of the high-energy spectrum are crucial to study the particle accelerators and probe the dominant emission mechanisms. We have carried out 125 hr of observations of NGC 1068 with the MAGIC telescopes in order to search for gamma-ray emission in the very-high-energy band. We did not detect significant gamma-ray emission, and set upper limits at the 95% confidence level to the gamma-ray flux above 200 GeV f < 5.1 × 10−13 cm−2 s−1. This limit improves previous constraints by about an order of magnitude and allows us to put tight constraints on the theoretical models for the gamma-ray emission. By combining the MAGIC observations with the Fermi-LAT spectrum we limit the parameter space (spectral slope, maximum energy) of the cosmic ray protons predicted by hadronuclear models for the gamma-ray emission, while we find that a model postulating leptonic emission from a semi-relativistic jet is fully consistent with the limits. We provide predictions for IceCube detection of the neutrino signal foreseen in the hadronic scenario. We predict a maximal IceCube neutrino event rate of 0.07 yr−1.
Related projects
Particle Astrophysics
The MAGIC Collaboration is integrated by 20 research institutes and university departments from Armenia, Bulgaria, Finland, Germany, Italy, Poland, Spain, Switzerland and USA. The collaboration comprises two 17m diameter telescopes, located at the Roque de los Muchachos Observatory, designed to measure the Cherenkov radiation associated with
Ramón
García López