Bibcode
DOI
Albert, J.; Aliu, E.; Anderhub, H.; Antoranz, P.; Armada, A.; Baixeras, C.; Barrio, J. A.; Bartko, H.; Bastieri, D.; Becker, J. K.; Bednarek, W.; Berger, K.; Bigongiari, C.; Biland, A.; Bock, R. K.; Bordas, P.; Bosch-Ramon, V.; Bretz, T.; Britvitch, I.; Camara, M.; Carmona, E.; Chilingarian, A.; Coarasa, J. A.; Commichau, S.; Contreras, J. L.; Cortina, J.; Costado, M. T.; Curtef, V.; Danielyan, V.; Dazzi, F.; De Angelis, A.; Delgado, C.; de los Reyes, R.; De Lotto, B.; Domingo-Santamaría, E.; Dorner, D.; Doro, M.; Errando, M.; Fagiolini, M.; Ferenc, D.; Fernández, E.; Firpo, R.; Flix, J.; Fonseca, M. V.; Font, L.; Fuchs, M.; Galante, N.; García-López, R. J.; Garczarczyk, M.; Gaug, M.; Giller, M.; Goebel, F.; Hakobyan, D.; Hayashida, M.; Hengstebeck, T.; Herrero, A.; Höhne, D.; Hose, J.; Hrupec, D.; Hsu, C. C.; Jacon, P.; Jogler, T.; Kosyra, R.; Kranich, D.; Kritzer, R.; Laille, A.; Lindfors, E.; Lombardi, S.; Longo, F.; López, J.; López, M.; Lorenz, E.; Majumdar, P.; Maneva, G.; Mannheim, K.; Mansutti, O.; Mariotti, M.; Martínez, M.; Mazin, D.; Merck, C.; Meucci, M.; Meyer, M.; Miranda, J. M.; Mirzoyan, R.; Mizobuchi, S.; Moralejo, A.; Nieto, D.; Nilsson, K.; Ninkovic, J.; Oña-Wilhelmi, E.; Otte, N.; Oya, I.; Paneque, D.; Panniello, M.; Paoletti, R.; Paredes, J. M.; Pasanen, M.; Pascoli, D.; Pauss, F.; Pegna, R. et al.
Bibliographical reference
The Astrophysical Journal, Volume 669, Issue 2, pp. 862-883.
Advertised on:
11
2007
Journal
Citations
518
Refereed citations
408
Description
The blazar Mrk 501 was observed at energies above 0.10 TeV with the
MAGIC Telescope from 2005 May through July. The high sensitivity of the
instrument enabled the determination of the flux and spectrum of the
source on a night-by-night basis. Throughout our observational campaign,
the flux from Mrk 501 was found to vary by an order of magnitude.
Intranight flux variability with flux-doubling times down to 2 minutes
was observed during the two most active nights, namely, June 30 and July
9. These are the fastest flux variations ever observed in Mrk 501. The
~20 minute long flare of July 9 showed an indication of a 4+/-1 minute
time delay between the peaks of F(<0.25 TeV) and F(>1.2 TeV),
which may indicate a progressive acceleration of electrons in the
emitting plasma blob. The flux variability was quantified for several
energy ranges and found to increase with the energy of the γ-ray
photons. The spectra hardened significantly with increasing flux, and
during the two most active nights, a spectral peak was clearly detected
at 0.43+/-0.06 and 0.25+/-0.07 TeV, respectively, for June 30 and July
9. There is no evidence of such a spectral feature for the other nights
at energies down to 0.10 TeV, thus suggesting that the spectral peak is
correlated with the source luminosity. These observed characteristics
could be accommodated in a synchrotron self-Compton framework in which
the increase in γ-ray flux is produced by a freshly injected (high
energy) electron population.