Investigation of the correlation patterns and the Compton dominance variability of Mrk 421 in 2017
Abstract
We present a detailed characterisation and theoretical interpretation of the broadband emission of the paradigmatic TeV blazar Mrk 421, with special focus on the multi-band flux correlations. The dataset has been collected through an extensive multiwavelength campaign organised between 2016 December and 2017 June. The instruments involved are MAGIC, FACT, Fermi-LAT, Swift, GASP-WEBT, OVRO, Medicina and Mets\"ahovi. Additionally, four deep exposures (several hours long) with simultaneous MAGIC and NuSTAR observations allowed a precise measurement of the falling segments of the two spectral components. The very-high-energy (VHE; E > 100 GeV) gamma rays and X-rays are positively correlated at zero time lag, but the strength and characteristics of the correlation change substantially across the various energy bands probed. The VHE versus X-ray fluxes follow different patterns, partly due to substantial changes in the Compton dominance during a few days without a simultaneous increase in the X-ray flux (i.e. orphan gamma-ray activity). Studying the broadband spectral energy distribution (SED) during the days including NuSTAR observations, we show that these changes can be explained within a one-zone leptonic model with a blob that increases its size over time. Our multi-band correlation study also hints at an anti-correlation between UV/optical and X-ray at a significance higher than 3 sigmas. A VHE flare observed on 2017 February 4 shows gamma-ray variability on multi-hour timescales, with a factor 10 increase in the TeV flux but only a moderate increase in the keV flux. The related broadband SED is better described by a two-zone leptonic scenario rather than by a one-zone scenario. We find that the flare can be produced by the appearance of a compact second blob populated by high energetic electrons spanning a narrow range of Lorentz factors.
Keywords
Cite
@article{arxiv.2106.05516,
title = {Investigation of the correlation patterns and the Compton dominance variability of Mrk 421 in 2017},
author = {MAGIC Collaboration and V. A. Acciari and S. Ansoldi and L. A. Antonelli and A. Arbet Engels and M. Artero and K. Asano and A. Babić and A. Baquero and U. Barres de Almeida and J. A. Barrio and I. Batković and J. Becerra González and W. Bednarek and L. Bellizzi and E. Bernardini and M. Bernardos and A. Berti and J. Besenrieder and W. Bhattacharyya and C. Bigongiari and O. Blanch and Ž. Bošnjak and G. Busetto and R. Carosi and G. Ceribella and M. Cerruti and Y. Chai and A. Chilingarian and S. Cikota and S. M. Colak and E. Colombo and J. L. Contreras and J. Cortina and S. Covino and G. D'Amico and V. D'Elia and P. Da Vela and F. Dazzi and A. De Angelis and B. De Lotto and M. Delfino and J. Delgado and C. Delgado Mendez and D. Depaoli and F. Di Pierro and L. Di Venere and E. Do Souto Espiñeira and D. Dominis Prester and A. Donini and M. Doro and V. Fallah Ramazani and A. Fattorini and G. Ferrara and M. V. Fonseca and L. Font and C. Fruck and S. Fukami and R. J. García López and M. Garczarczyk and S. Gasparyan and M. Gaug and N. Giglietto and F. Giordano and P. Gliwny and N. Godinović and J. G. Green and D. Green and D. Hadasch and A. Hahn and L. Heckmann and J. Herrera and J. Hoang and D. Hrupec and M. Hütten and T. Inada and S. Inoue and K. Ishio and Y. Iwamura and I. Jiménez and J. Jormanainen and L. Jouvin and Y. Kajiwara and M. Karjalainen and D. Kerszberg and Y. Kobayashi and H. Kubo and J. Kushida and A. Lamastra and D. Lelas 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 B. Machado de Oliveira Fraga and C. Maggio and P. Majumdar and M. Makariev and M. Mallamaci and G. Maneva and M. Manganaro and L. Maraschi and M. Mariotti and M. Martínez and D. Mazin and S. Menchiari and S. Mender and S. Mićanović and D. Miceli and T. Miener and M. Minev and J. M. Miranda and R. Mirzoyan and E. Molina and A. Moralejo and D. Morcuende and V. Moreno and E. Moretti and V. Neustroev and C. Nigro and K. Nilsson and K. Nishijima and K. Noda and S. Nozaki and Y. Ohtani and T. Oka and J. Otero-Santos and S. Paiano and M. Palatiello and D. Paneque and R. Paoletti and J. M. Paredes and L. Pavletić and P. Peñil and C. Perennes and M. Persic and P. G. Prada Moroni and E. Prandini and C. Priyadarshi and I. Puljak and M. Ribó and J. Rico and C. Righi and A. Rugliancich and L. Saha and N. Sahakyan and T. Saito and S. Sakurai and K. Satalecka and F. G. Saturni and K. Schmidt and T. Schweizer and J. Sitarek and I. Šnidarić and D. Sobczynska and A. Spolon and A. Stamerra and D. Strom and M. Strzys and Y. Suda and T. Surić and M. Takahashi and F. Tavecchio and P. Temnikov and T. Terzić and M. Teshima and L. Tosti and S. Truzzi and A. Tutone and S. Ubach and J. van Scherpenberg and G. Vanzo and M. Vazquez Acosta and S. Ventura and V. Verguilov and C. F. Vigorito and V. Vitale and I. Vovk and M. Will and C. Wunderlich and D. Zarić and FACT Collaboration and : and D. Baack and M. Balbo and N. Biederbeck and A. Biland and T. Bretz and J. Buss and D. Dorner and L. Eisenberger and D. Elsaesser and D. Hildebrand and R. Iotov and K. Mannheim and D. Neise and M. Noethe and A. Paravac and W. Rhode and B. Schleicher and V. Sliusar and R. Walter and Other groups and collaborations and : and F. D'Ammando and D. Horan and A. Y. Lien and M. Baloković and G. M. Madejski and M. Perri and F. Verrecchia and C. Leto and A. Lähteenmäki and M. Tornikoski and V. Ramakrishnan and E. Järvelä and R. J. C. Vera and M. Villata and C. M. Raiteri and A. C. Gupta and A. Pandey and A. Fuentes and I. Agudo and C. Casadio and E. Semkov and S. Ibryamov and A. Marchini and R. Bachev and A. Strigachev and E. Ovcharov and V. Bozhilov and A. Valcheva and E. Zaharieva and G. Damljanovic and O. Vince and V. M. Larionov and G. A. Borman and T. S. Grishina and V. A. Hagen-Thorn and E. N. Kopatskaya and E. G. Larionova and L. V. Larionova and D. A. Morozova and A. A. Nikiforova and S. S. Savchenko and I. S. Troitskiy and Y. V. Troitskaya and A. A. Vasilyev and O. A. Merkulova and W. P. Chen and M. Samal and H. C. Lin and J. W. Moody and A. C. Sadun and S. G. Jorstad and A. P. Marscher and Z. R. Weaver and M. Feige and J. Kania and M. Kopp and L. Kunkel and D. Reinhart and A. Scherbantin and L. Schneider and C. Lorey and J. A. Acosta-Pulido and M. I. Carnerero and D. Carosati and S. O. Kurtanidze and O. M. Kurtanidze and M. G. Nikolashvili and R. G. Chanishvili and R. A. Chigladze and R. Z. Ivanidze and G. N. Kimeridze and L. A. Sigua and M. D. Joner and M. Spencer and M. Giroletti and N. Marchili and S. Righini and N. Rizzi and G. Bonnoli},
journal= {arXiv preprint arXiv:2106.05516},
year = {2021}
}
Comments
38 pages, 23 figures, accepted for publication in Astronomy and Astrophysics. Corresponding authors: Axel Arbet-Engels, David Paneque