The 2009 multiwavelength campaign on Mrk 421: Variability and correlation studies
Abstract
We performed a 4.5-month multi-instrument campaign (from radio to VHE gamma rays) on Mrk421 between January 2009 and June 2009, which included VLBA, F-GAMMA, GASP-WEBT, Swift, RXTE, Fermi-LAT, MAGIC, and Whipple, among other instruments and collaborations. Mrk421 was found in its typical (non-flaring) activity state, with a VHE flux of about half that of the Crab Nebula, yet the light curves show significant variability at all wavelengths, the highest variability being in the X-rays. We determined the power spectral densities (PSD) at most wavelengths and found that all PSDs can be described by power-laws without a break, and with indices consistent with pink/red-noise behavior. We observed a harder-when-brighter behavior in the X-ray spectra and measured a positive correlation between VHE and X-ray fluxes with zero time lag. Such characteristics have been reported many times during flaring activity, but here they are reported for the first time in the non-flaring state. We also observed an overall anti-correlation between optical/UV and X-rays extending over the duration of the campaign. The harder-when-brighter behavior in the X-ray spectra and the measured positive X-ray/VHE correlation during the 2009 multi-wavelength campaign suggests that the physical processes dominating the emission during non-flaring states have similarities with those occurring during flaring activity. In particular, this observation supports leptonic scenarios as being responsible for the emission of Mrk421 during non-flaring activity. Such a temporally extended X-ray/VHE correlation is not driven by any single flaring event, and hence is difficult to explain within the standard hadronic scenarios. The highest variability is observed in the X-ray band, which, within the one-zone synchrotron self-Compton scenario, indicates that the electron energy distribution is most variable at the highest energies.
Keywords
Cite
@article{arxiv.1502.02650,
title = {The 2009 multiwavelength campaign on Mrk 421: Variability and correlation studies},
author = {MAGIC Collaboration and J. Aleksić and S. Ansoldi and L. A. Antonelli and P. Antoranz and A. Babic and P. Bangale and U. Barres de Almeida and J. A. Barrio and J. Becerra González and W. Bednarek and K. Berger and E. Bernardini and A. Biland and O. Blanch and R. K. Bock and S. Bonnefoy and G. Bonnoli and F. Borracci and T. Bretz and E. Carmona and A. Carosi and D. Carreto Fidalgo and P. Colin and E. Colombo and J. L. Contreras and J. Cortina and S. Covino and P. Da Vela and F. Dazzi and A. De Angelis and G. De Caneva and B. De Lotto and C. Delgado Mendez and M. Doert and A. Domínguez and D. Dominis Prester and D. Dorner and M. Doro and S. Einecke and D. Eisenacher and D. Elsaesser and E. Farina and D. Ferenc and M. V. Fonseca and L. Font and K. Frantzen and C. Fruck and R. J. García López and M. Garczarczyk and D. Garrido Terrats and M. Gaug and G. Giavitto and N. Godinović and A. González Mu\ noz and S. R. Gozzini and A. Hadamek and D. Hadasch and A. Herrero and D. Hildebrand and J. Hose and D. Hrupec and W. Idec and V. Kadenius and H. Kellermann and M. L. Knoetig and J. Krause and J. Kushida and A. La Barbera and D. Lelas and N. Lewandowska and E. Lindfors and F. Longo and S. Lombardi and M. López and R. López-Coto and A. López-Oramas and E. Lorenz and I. Lozano and M. Makariev and K. Mallot and G. Maneva and N. Mankuzhiyil and K. Mannheim and L. Maraschi and B. Marcote and M. Mariotti and M. Martínez and D. Mazin and U. Menzel and M. Meucci and J. M. Miranda and R. Mirzoyan and A. Moralejo and P. Munar-Adrover and D. Nakajima and A. Niedzwiecki and K. Nilsson and N. Nowak and R. Orito and A. Overkemping and S. Paiano and M. Palatiello and D. Paneque and R. Paoletti and J. M. Paredes and X. Paredes-Fortuny and S. Partini and M. Persic and F. Prada and P. G. Prada Moroni and E. Prandini and S. Preziuso and I. Puljak and R. Reinthal and W. Rhode and M. Ribó and J. Rico and J. Rodriguez Garcia and S. Rügamer and A. Saggion and K. Saito and M. Salvati and K. Satalecka and V. Scalzotto and V. Scapin and C. Schultz and T. Schweizer and S. N. Shore and A. Sillanpää and J. Sitarek and I. Snidaric and D. Sobczynska and F. Spanier and V. Stamatescu and A. Stamerra and T. Steinbring and J. Storz and S. Sun and T. Surić and L. Takalo and F. Tavecchio and P. Temnikov and T. Terzić and D. Tescaro and M. Teshima and J. Thaele and O. Tibolla and D. F. Torres and T. Toyama and A. Treves and M. Uellenbeck and P. Vogler and R. M. Wagner and F. Zandanel and R. Zanin and VERITAS collaboration and : and S. Archambault and B. Behera and M. Beilicke and W. Benbow and R. Bird and J. H. Buckley and V. Bugaev and M. Cerruti and X. Chen and L. Ciupik and E. Collins-Hughes and W. Cui and J. Dumm and J. D. Eisch and A. Falcone and S. Federici and Q. Feng and J. P. Finley and H. Fleischhack and P. Fortin and L. Fortson and A. Furniss and S. Griffin and S. T. Griffiths and J. Grube and G. Gyuk and D. Hanna and J. Holder and G. Hughes and T. B. Humensky and C. A. Johnson and P. Kaaret and M. Kertzman and Y. Khassen and D. Kieda and H. Krawczynski and F. Krennrich and S. Kumar and M. J. Lang and G. Maier and S. McArthur and K. Meagher and P. Moriarty and R. Mukherjee and R. A. Ong and A. N. Otte and N. Park and A. Pichel and M. Pohl and A. Popkow and H. Prokoph and J. Quinn and K. Ragan and J. Rajotte and P. T. Reynolds and G. T. Richards and E. Roache and A. C. Rovero and G. H. Sembroski and K. Shahinyan and D. Staszak and I. Telezhinsky and M. Theiling and J. V. Tucci and J. Tyler and A. Varlotta and S. P. Wakely and T. C. Weekes and A. Weinstein and R. Welsing and A. Wilhelm and D. A. Williams and B. Zitzer and External collaborators and : and M. Villata and C. Raiteri and H. D. Aller and M. F. Aller and W. P. Chen and B. Jordan and E. Koptelova and O. M. Kurtanidze and A. Lähteenmäki and B. McBreen and V. M. Larionov and C. S. Lin and M. G. Nikolashvili and E. Angelakis and M. Capalbi and A. Carrami\ nana and L. Carrasco and P. Cassaro and A. Cesarini and L. Fuhrmann and M. Giroletti and T. Hovatta and T. P. Krichbaum and H. A. Krimm and W. Max-Moerbeck and J. W. Moody and G. Maccaferri and Y. Mori and I. Nestoras and A. Orlati and C. Pace and R. Pearson and M. Perri and A. C. S. Readhead and J. L. Richards and A. C. Sadun and T. Sakamoto and J. Tammi and M. Tornikoski and Y. Yatsu and A. Zook},
journal= {arXiv preprint arXiv:1502.02650},
year = {2016}
}
Comments
Accepted for publication in A&A, 18 pages, 14 figures (v2 has a small modification in the acknowledgments, and also corrects a typo in the field "author" in the metadata)