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, A.; López, M.; 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.
Referencia bibliográfica
Astronomy and Astrophysics, Volume 542, id.A100
Fecha de publicación:
6
2012
Revista
Número de citas
68
Número de citas referidas
61
Descripción
Context. The blazar Markarian 421 is one of the brightest TeV gamma-ray
sources of the northern sky. From December 2007 until June 2008 it was
intensively observed in the very high energy (VHE, E > 100 GeV) band
by the single-dish Major Atmospheric Gamma-ray Imaging Cherenkov
telescope (MAGIC-I). Aims: We aimed to measure the physical
parameters of the emitting region of the blazar jet during active
states. Methods: We performed a dense monitoring of the source in
VHE with MAGIC-I, and also collected complementary data in soft X-rays
and optical-UV bands; then, we modeled the spectral energy distributions
(SED) derived from simultaneous multi-wavelength data within the
synchrotron self-Compton (SSC) framework. Results: The source
showed intense and prolonged γ-ray activity during the whole
period, with integral fluxes (E > 200 GeV) seldom below the level of
the Crab Nebula, and up to 3.6 times this value. Eight datasets of
simultaneous optical-UV (KVA, Swift/UVOT), soft X-ray (Swift/XRT) and
MAGIC-I VHE data were obtained during different outburst phases. The
data constrain the physical parameters of the jet, once the spectral
energy distributions obtained are interpreted within the framework of a
single-zone SSC leptonic model. Conclusions: The main outcome of
the study is that within the homogeneous model high Doppler factors (40
≤ δ ≤ 80) are needed to reproduce the observed SED; but this
model cannot explain the observed short time-scale variability, while it
can be argued that inhomogeneous models could allow for less extreme
Doppler factors, more intense magnetic fields and shorter electron
cooling times compatible with hour or sub-hour scale variability.
Proyectos relacionados
Astrofísica de Partículas
El Grupo de Astrofísica de Partículas del IAC participa activamente en tres grandes colaboraciones internacionales de astrofísica de muy altas energías: AMS (Alpha Magnetic Spectrometer), los telescopios de radiación Cherenkov MAGIC I y II, y el Cherenkov Telescope Array (CTA). AMS es un detector de partículas diseñado para operar en el espacio, a
Ramón
García López