Bibcode
Aleksić, J.; Alvarez, E. A.; Antonelli, L. A.; Antoranz, P.; Asensio, M.; Backes, M.; Barres de Almeida, U.; Barrio, J. A.; Bastieri, D.; Becerra-González, J.; Bednarek, W.; Berger, K.; Bernardini, E.; Biland, A.; Blanch, O.; Bock, R. K.; Boller, A.; Bonnoli, G.; Borla Tridon, D.; Bretz, T.; Cañellas, A.; Carmona, E.; Carosi, A.; Colin, P.; Colombo, E.; Contreras, J. L.; Cortina, J.; Cossio, L.; Covino, S.; da Vela, P.; Dazzi, F.; de Angelis, A.; de Caneva, G.; de Cea Del Pozo, E.; de Lotto, B.; Delgado-Mendez, C.; Diago-Ortega, A.; Doert, M.; Domínguez, A.; Dominis Prester, D.; Dorner, D.; Doro, M.; Eisenacher, D.; Elsaesser, D.; Ferenc, D.; Fonseca, M. V.; Font, L.; Fruck, C.; García-López, R. J.; Garczarczyk, M.; Garrido, D.; Giavitto, G.; Godinović, N.; Gozzini, S. R.; Hadasch, D.; Häfner, D.; Herrero, A.; Hildebrand, D.; Höhne-Mönch, D.; Hose, J.; Hrupec, D.; Huber, B.; Jogler, T.; Kadenius, V.; Kellermann, H.; Klepser, S.; Krähenbühl, T.; Krause, J.; La Barbera, A.; Lelas, D.; Leonardo, E.; Lewandowska, N.; Lindfors, E.; Lombardi, S.; López, M.; López-Coto, R.; López-Oramas, A.; Lorenz, E.; Makariev, M.; Maneva, G.; Mankuzhiyil, N.; Mannheim, K.; Maraschi, L.; Mariotti, M.; Martínez, M.; Mazin, D.; Meucci, M.; Miranda, J. M.; Mirzoyan, R.; Moldón, J.; Moralejo, A.; Munar-Adrover, P.; Niedzwiecki, A.; Nieto, D.; Nilsson, K.; Nowak, N.; Orito, R.; Paiano, S.; Paneque, D.; Paoletti, R. et al.
Bibliographical reference
Astronomy and Astrophysics, Volume 539, id.L2
Advertised on:
3
2012
Journal
Citations
94
Refereed citations
69
Description
We report on the detection of very-high energy (VHE, E > 100 GeV)
γ-ray emission from NGC 1275, the central radio
galaxy of the Perseus cluster of galaxies. The source has been detected
by the MAGIC telescopes with a statistical significance of 6.6σ
above 100 GeV in 46 h of stereo observations carried out between August
2010 and February 2011. The measured differential energy spectrum
between 70 GeV and 500 GeV can be described by a power law with a steep
spectral index of Γ = -4.1 ± 0.7stat ±
0.3syst, and the average flux above 100 GeV is
Fγ = (1.3 ± 0.2stat ±
0.3syst) × 10-11 cm-2
s-1. These results, combined with the power-law spectrum
measured in the first two years of observations by the Fermi-LAT above
100 MeV, with a spectral index of Γ ≃ - 2.1, strongly suggest
the presence of a break or cut-off around tens of GeV in the
NGC 1275 spectrum. The light curve of the source
above 100 GeV does not show hints of variability on a month time scale.
Finally, we report on the nondetection in the present data of the radio
galaxy IC 310, previously discovered by the Fermi-LAT
and MAGIC. The derived flux upper limit
FU.L.γ (>300 GeV) = 1.2 ×
10-12 cm-2 s-1 is a factor ~ 3 lower
than the mean flux measured by MAGIC between October 2009 and February
2010, thus confirming the year time-scale variability of the source at
VHE.
Related projects
Particle Astrophysics
The members of the Particle Astrophysics Group of the IAC participate actively in three large international collaborations of high-energy astrophysics: AMS-02 (Alpha Magnetic Spectrometer), the Cherenkov radiation telescopes MAGIC I and II and the Cherenkov Telescope Array Observatory ( CTAO). We also participate in the ASTRI mini-array, the gamma
Mónica Luisa
Vázquez Acosta