Characterization of Markarian 421 during its most violent year: Multiwavelength variability and correlations
Abstract
Mrk 421 was in its most active state around early 2010, which led to the highest TeV gamma-ray flux ever recorded from any active galactic nuclei. We aim to characterize the multiwavelength behavior during this exceptional year for Mrk 421, and evaluate whether it is consistent with the picture derived with data from other less exceptional years. We investigated the period from November 5, 2009, (MJD 55140) until July 3, 2010, (MJD 55380) with extensive coverage from very-high-energy (VHE; E100GeV) gamma rays to radio with MAGIC, VERITAS, Fermi-LAT, RXTE, Swift, GASP-WEBT, VLBA, and a variety of additional optical and radio telescopes. We investigated the variability and correlation behavior among different energy bands in great detail. We find the strongest variability in X-rays and VHE gamma rays, and PSDs compatible with power-law functions. We observe strong correlations between X-rays and VHE gamma rays. We also report a marginally significant positive correlation between high-energy (HE; E100MeV) gamma rays and the ultraviolet band. We detected marginally significant correlations between the HE and VHE gamma rays, and between HE gamma rays and the X-ray, that disappear when the large flare in February 2010 is excluded from the correlation study. The activity of Mrk 421 also yielded the first ejection of features in the VLBA images of the jet of Mrk 421. Yet the large uncertainties in the ejection times of these radio features prevent us from firmly associating them to the specific flares recorded during the campaign. We also show that the collected multi-instrument data are consistent with a scenario where the emission is dominated by two regions, a compact and extended zone, which could be considered as a simplified implementation of an energy-stratified jet as suggested by recent IXPE observations.
Keywords
Cite
@article{arxiv.2501.03831,
title = {Characterization of Markarian 421 during its most violent year: Multiwavelength variability and correlations},
author = {K. Abe and S. Abe and J. Abhir and A. Abhishek and V. A. Acciari and A. Aguasca-Cabot and I. Agudo and T. Aniello and S. Ansoldi and L. A. Antonelli and A. Arbet Engels and C. Arcaro and K. Asano and D. Baack and A. Babić and U. Barres de Almeida and J. A. Barrio and I. Batković and A. Bautista and J. Baxter and J. Becerra González and W. Bednarek and E. Bernardini and J. Bernete and A. Berti and J. Besenrieder and C. Bigongiari and A. Biland and O. Blanch and G. Bonnoli and Ž. Bošnjak and E. Bronzini and I. Burelli and A. Campoy-Ordaz and R. Carosi and M. Carretero-Castrillo and A. J. Castro-Tirado and D. Cerasole and G. Ceribella and Y. Chai and A. Cifuentes and E. Colombo and J. L. Contreras and J. Cortina and S. Covino and G. D'Amico and F. D'Ammando and V. D'Elia and P. Da Vela and F. Dazzi and A. De Angelis and B. De Lotto and R. de Menezes and M. Delfino and J. Delgado and C. Delgado Mendez and F. Di Pierro and R. Di Tria and L. Di Venere and D. Dominis Prester and A. Donini and D. Dorner and M. Doro and L. Eisenberger and D. Elsaesser and J. Escudero and L. Fariña and A. Fattorini and L. Foffano and L. Font and S. Fröse and S. Fukami and Y. Fukazawa and R. J. García López and M. Garczarczyk and S. Gasparyan and M. Gaug and J. G. Giesbrecht Paiva and N. Giglietto and F. Giordano and P. Gliwny and N. Godinović and T. Gradetzke and R. Grau and D. Green and J. G. Green and P. Günther and D. Hadasch and A. Hahn and T. Hassan and L. Heckmann and J. Herrera Llorente and D. Hrupec and R. Imazawa and K. Ishio and I. Jiménez Martínez and J. Jormanainen and S. Kankkunen and T. Kayanoki and D. Kerszberg and G. W. Kluge and P. M. Kouch and H. Kubo and J. Kushida and M. Láinez and A. Lamastra and F. Leone and E. Lindfors and S. Lombardi and F. Longo and R. López-Coto and M. López-Moya and A. López-Oramas and S. Loporchio and A. Lorini and P. Majumdar and M. Makariev and G. Maneva and M. Manganaro and S. Mangano and K. Mannheim and M. Mariotti and M. Martínez and M. Martínez-Chicharro and A. Mas-Aguilar and D. Mazin and S. Menchiari and S. Mender and D. Miceli and T. Miener and J. M. Miranda and R. Mirzoyan and M. Molero González and E. Molina and H. A. Mondal and A. Moralejo and D. Morcuende and T. Nakamori and C. Nanci and V. Neustroev and L. Nickel and C. Nigro and L. Nikolić and K. Nilsson and K. Nishijima and T. Njoh Ekoume and K. Noda and S. Nozaki and A. Okumura and J. Otero-Santos and S. Paiano and D. Paneque and R. Paoletti and J. M. Paredes and M. Peresano and M. Persic and M. Pihet and G. Pirola and F. Podobnik and P. G. Prada Moroni and E. Prandini and G. Principe and W. Rhode and M. Ribó and J. Rico and C. Righi and N. Sahakyan and T. Saito and F. G. Saturni and K. Schmidt and F. Schmuckermaier and J. L. Schubert and T. Schweizer and A. Sciaccaluga and G. Silvestri and J. Sitarek and D. Sobczynska and A. Stamerra and J. Strišković and D. Strom and Y. Suda and H. Tajima and M. Takahashi and R. Takeishi and F. Tavecchio and P. Temnikov and K. Terauchi and T. Terzić and M. Teshima and S. Truzzi and A. Tutone and S. Ubach and J. van Scherpenberg and S. Ventura and G. Verna and I. Viale and C. F. Vigorito and V. Vitale and I. Vovk and R. Walter and F. Wersig and M. Will and T. Yamamoto and S. G. Jorstad and A. P. Marscher and M. Perri and C. Leto and F. Verrecchia and M. Aller and W. Max-Moerbeck and A. C. S. Readhead and A. Lähteenmäki and M. Tornikoski and M. A. Gurwell and A. E. Wehrle},
journal= {arXiv preprint arXiv:2501.03831},
year = {2025}
}
Comments
Accepted for publication in Astronomy & Astrophysics. Corresponding authors: Felix Schmuckermaier, David Paneque, Axel Arbet Engels