Bibcode
Aleksić, J.; Antonelli, L. A.; Antoranz, P.; Backes, M.; Baixeras, C.; Balestra, S.; Barrio, J. A.; Bastieri, D.; Becerra-González, J.; Bednarek, W.; Berdyugin, A.; Berger, K.; Bernardini, E.; Biland, A.; Bock, R. K.; Bonnoli, G.; Bordas, P.; Borla Tridon, D.; Bosch-Ramon, V.; Bose, D.; Braun, I.; Bretz, T.; Britzger, D.; Camara, M.; Carmona, E.; Carosi, A.; Colin, P.; Commichau, S.; Contreras, J. L.; Cortina, J.; Costado, M. T.; Covino, S.; Dazzi, F.; De Angelis, A.; De Cea del Pozo, E.; De los Reyes, R.; De Lotto, B.; De Maria, M.; De Sabata, F.; Delgado-Méndez, C.; Doert, M.; Domínguez, A.; Dominis Prester, D.; Dorner, D.; Doro, M.; Elsaesser, D.; Errando, M.; Ferenc, D.; Fonseca, M. V.; Font, L.; Galante, N.; García López, R. J.; Garczarczyk, M.; Gaug, M.; Godinovic, N.; Hadasch, D.; Herrero, A.; Hildebrand, D.; Höhne-Mönch, D.; Hose, J.; Hrupec, D.; Hsu, C. C.; Jogler, T.; Klepser, S.; Krähenbühl, T.; Kranich, D.; La Barbera, A.; Laille, A.; Leonardo, E.; Lindfors, E.; Lombardi, S.; Longo, F.; López, M.; Lorenz, E.; Majumdar, P.; Maneva, G.; Mankuzhiyil, N.; Mannheim, K.; Maraschi, L.; Mariotti, M.; Martínez, M.; Mazin, D.; Meucci, M.; Miranda, J. M.; Mirzoyan, R.; Miyamoto, H.; Moldón, J.; Moles, M.; Moralejo, A.; Nieto, D.; Nilsson, K.; Ninkovic, J.; Orito, R.; Oya, I.; Paiano, S.; Paoletti, R.; Paredes, J. M.; Partini, S.; Pasanen, M.; Pascoli, D. et al.
Bibliographical reference
The Astrophysical Journal, Volume 710, Issue 1, pp. 634-647 (2010).
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2
2010
Journal
Citations
137
Refereed citations
97
Description
The Perseus galaxy cluster was observed by the MAGIC Cherenkov telescope
for a total effective time of 24.4 hr during 2008 November and December.
The resulting upper limits on the γ-ray emission above 100 GeV are
in the range of 4.6-7.5 × 10-12 cm-2
s-1 for spectral indices from -1.5 to -2.5, thereby
constraining the emission produced by cosmic rays, dark matter
annihilations, and the central radio galaxy NGC 1275. Results are
compatible with cosmological cluster simulations for the
cosmic-ray-induced γ-ray emission, constraining the average cosmic
ray-to-thermal pressure to <4% for the cluster core region (<8%
for the entire cluster). Using simplified assumptions adopted in earlier
work (a power-law spectrum with an index of -2.1, constant cosmic
ray-to-thermal pressure for the peripheral cluster regions while
accounting for the adiabatic contraction during the cooling flow
formation), we would limit the ratio of cosmic ray-to-thermal energy to
E CR/E th < 3%. Improving the sensitivity of
this observation by a factor of about 7 will enable us to scrutinize the
hadronic model for the Perseus radio mini-halo: a non-detection of
γ-ray emission at this level implies cosmic ray fluxes that are
too small to produce enough electrons through hadronic interactions with
the ambient gas protons to explain the observed synchrotron emission.
The upper limit also translates into a level of γ-ray emission
from possible annihilations of the cluster dark matter (the dominant
mass component) that is consistent with boost factors of ~104
for the typically expected dark matter annihilation-induced emission.
Finally, the upper limits obtained for the γ-ray emission of the
central radio galaxy NGC 1275 are consistent with the recent detection
by the Fermi-LAT satellite. Due to the extremely large Doppler factors
required for the jet, a one-zone synchrotron self-Compton model is
implausible in this case. We reproduce the observed spectral energy
density by using the structured jet (spine-layer) model which has
previously been adopted to explain the high-energy emission of radio
galaxies.
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