Bibcode
Aleksić, J.; Alvarez, E. A.; Antonelli, L. A.; Antoranz, P.; Asensio, M.; Backes, M.; Barrio, J. A.; Bastieri, D.; Becerra-González, J.; Bednarek, W.; Berdyugin, A.; Berger, K.; Bernardini, E.; Biland, A.; Blanch, O.; Bock, R. K.; Boller, A.; Bonnoli, G.; Borla Tridon, D.; Braun, I.; Bretz, T.; Cañellas, A.; Carmona, E.; Carosi, A.; Colin, P.; Colombo, E.; Contreras, J. L.; Cortina, J.; Cossio, L.; Covino, S.; 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.; Elsaesser, D.; Ferenc, D.; Fonseca, M. V.; Font, L.; Fruck, C.; García-López, R. J.; Garczarczyk, M.; Garrido, D.; Giavitto, G.; Godinović, N.; Hadasch, D.; Häfner, D.; Herrero, A.; Hildebrand, D.; Höhne-Mönch, D.; Hose, J.; Hrupec, D.; Huber, B.; Jogler, T.; Kellermann, H.; Klepser, S.; Krähenbühl, T.; Krause, J.; La Barbera, A.; Lelas, D.; Leonardo, E.; Lindfors, E.; Lombardi, S.; López, M.; 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.; Miyamoto, H.; Moldón, J.; Moralejo, A.; Munar-Adrover, P.; Nieto, D.; Nilsson, K.; Orito, R.; Oya, I.; Paneque, D.; Paoletti, R.; Pardo, S.; Paredes, J. M.; Partini, S.; Pasanen, M.; Pauss, F.; Perez-Torres, M. A. et al.
Bibliographical reference
The Astrophysical Journal, Volume 748, Issue 1, article id. 46 (2012).
Advertised on:
3
2012
Journal
Citations
52
Refereed citations
44
Description
We present the results of five years (2005-2009) of MAGIC observations
of the BL Lac object PG 1553+113 at very high energies (VHEs; E > 100
GeV). Power-law fits of the individual years are compatible with a
steady mean photon index Γ = 4.27 ± 0.14. In the last three
years of data, the flux level above 150 GeV shows a clear variability
(probability of constant flux < 0.001%). The flux variations are
modest, lying in the range from 4% to 11% of the Crab Nebula flux.
Simultaneous optical data also show only modest variability that seems
to be correlated with VHE gamma-ray variability. We also performed a
temporal analysis of (all available) simultaneous Fermi/Large Area
Telescope data of PG 1553+113 above 1 GeV, which reveals hints of
variability in the 2008-2009 sample. Finally, we present a combination
of the mean spectrum measured at VHEs with archival data available for
other wavelengths. The mean spectral energy distribution can be modeled
with a one-zone synchrotron self-Compton model, which gives the main
physical parameters governing the VHE emission in the blazar jet.
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