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
91
Refereed citations
66
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 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