Mrk 421 active state in 2008: the MAGIC view, simultaneous multi-wavelength observations and SSC model constrained
Abstract
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 gamma-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 <= delta <= 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.
Cite
@article{arxiv.1106.1589,
title = {Mrk 421 active state in 2008: the MAGIC view, simultaneous multi-wavelength observations and SSC model constrained},
author = {J. Aleksic and E. A. Alvarez and L. A. Antonelli and P. Antoranz and M. Asensio and M. Backes and J. A. Barrio and D. Bastieri and J. Becerra Gonzalez and W. Bednarek and A. Berdyugin and K. Berger and E. Bernardini and A. Biland and O. Blanch and R. K. Bock and A. Boller and G. Bonnoli and D. Borla Tridon and I. Braun and T. Bretz and A. Canellas and E. Carmona and A. Carosi and P. Colin and E. Colombo and J. L. Contreras and J. Cortina and L. Cossio and S. Covino and F. Dazzi and A. De Angelis and G. De Caneva and E. De Cea del Pozo and B. De Lotto and C. Delgado Mendez and A. Diago Ortega and M. Doert and A. Dominguez and D. Dominis Prester and D. Dorner and M. Doro and D. Elsaesser and D. Ferenc and M. V. Fonseca and L. Font and C. Fruck and R. J. Garcia Lopez and M. Garczarczyk and D. Garrido and G. Giavitto and N. Godinovic and D. Hadasch and D. Häfner and A. Herrero and D. Hildebrand and D. Höhne-Mönch and J. Hose and D. Hrupec and B. Huber and T. Jogler and H. Kellermann and S. Klepser and T. Krahenbuh and J. Krause and A. La Barbera and D. Lelas and E. Leonardo and E. Lindfors and S. Lombardi and A. Lopez and M. Lopez and E. Lorenz and M. Makariev and G. Maneva and N. Mankuzhiyil and K. Mannheim and L. Maraschi and M. Mariotti and M. Martinez and D. Mazin and M. Meucci and J. M. Miranda and R. Mirzoyan and H. Miyamoto and J. Moldon and A. Moralejo and P. Munar-Adrover and D. Nieto and K. Nilsson and R. Orito and I. Oya and D. Paneque and R. Paoletti and S. Pardo and J. M. Paredes and S. Partini and M. Pasanen and F. Pauss and M. A. Perez-Torres and M. Persic and L. Peruzzo and M. Pilia and J. Pochon and F. Prada and P. G. Prada Moroni and E. Prandini and I. Puljak and I. Reichardt and R. Reinthal and W. Rhode and M. Ribo and J. Rico and S. Rügamer and A. Saggion and K. Saito and T. Y. Saito and M. Salvati and K. Satalecka and V. Scalzotto and V. Scapin and C. Schultz and T. Schweizer and M. Shayduk and S. N. Shore and A. Sillanpaa and J. Sitarek and D. Sobczynska and F. Spanier and S. Spiro and A. Stamerra and B. Steinke and J. Storz and N. Strah and T. Suric and L. Takalo and H. Takami and F. Tavecchio and P. Temnikov and T. Terzic and D. Tescaro and M. Teshima and O. Tibolla and D. F. Torres and A. Treves and M. Uellenbeck and H. Vankov and P. Vogler and R. M. Wagner and Q. Weitzel and V. Zabalza and F. Zandanel and R. Zanin},
journal= {arXiv preprint arXiv:1106.1589},
year = {2015}
}
Comments
12 pages, 7 figures. Accepted for publication in A&A 7 January 2012