Investigation of the correlation patterns and the Compton dominance variability of Mrk 421 in 2017
Creators: name: MAGIC Collaboration
name: Acciari, V. A.
name: Ansoldi, S.
name: Antonelli, L. A.
name: Engels, A. Arbet
name: Artero, M.
name: Asano, K.
name: Babić, A.
name: Baquero, A.
name: de Almeida, U. Barres
name: Barrio, J. A.
name: Batković, I.
name: González, J. Becerra
name: Bednarek, W.
name: Bellizzi, L.
name: Bernardini, E.
name: Bernardos, M.
name: Berti, A.
name: Besenrieder, J.
name: Bhattacharyya, W.
name: Bigongiari, C.
name: Blanch, O.
name: Bošnjak, Ž.
name: Busetto, G.
name: Carosi, R.
name: Ceribella, G.
name: Cerruti, M.
name: Chai, Y.
name: Chilingarian, A.
name: Cikota, S.
name: Colak, S. M.
name: Colombo, E.
name: Contreras, J. L.
name: Cortina, J.
name: Covino, S.
name: D'Amico, G.
name: D'Elia, V.
name: Da Vela, P.
name: Dazzi, F.
name: De Angelis, A.
name: De Lotto, B.
name: Delfino, M.
name: Delgado, J.
name: Mendez, C. Delgado
name: Depaoli, D.
name: Di Pierro, F.
name: Di Venere, L.
name: Espiñeira, E. Do Souto
name: Prester, D. Dominis
name: Donini, A.
name: Doro, M.
name: Ramazani, V. Fallah
name: Fattorini, A.
name: Ferrara, G.
name: Fonseca, M. V.
name: Font, L.
name: Fruck, C.
name: Fukami, S.
name: López, R. J. García
name: Garczarczyk, M.
name: Gasparyan, S.
name: Gaug, M.
name: Giglietto, N.
name: Giordano, F.
name: Gliwny, P.
name: Godinović, N.
name: Green, J. G.
name: Green, D.
name: Hadasch, D.
name: Hahn, A.
name: Heckmann, L.
name: Herrera, J.
name: Hoang, J.
name: Hrupec, D.
name: Hütten, M.
name: Inada, T.
name: Inoue, S.
name: Ishio, K.
name: Iwamura, Y.
name: Jiménez, I.
name: Jormanainen, J.
name: Jouvin, L.
name: Kajiwara, Y.
name: Karjalainen, M.
name: Kerszberg, D.
name: Kobayashi, Y.
name: Kubo, H.
name: Kushida, J.
name: Lamastra, A.
name: Lelas, D.
name: Leone, F.
name: Lindfors, E.
name: Lombardi, S.
name: Longo, F.
name: López-Coto, R.
name: López-Moya, M.
name: López-Oramas, A.
name: Loporchio, S.
name: Fraga, B. Machado de Oliveira
name: Maggio, C.
name: Majumdar, P.
name: Makariev, M.
name: Mallamaci, M.
name: Maneva, G.
name: Manganaro, M.
name: Maraschi, L.
name: Mariotti, M.
name: Martínez, M.
name: Mazin, D.
name: Menchiari, S.
name: Mender, S.
name: Mićanović, S.
name: Miceli, D.
name: Miener, T.
name: Minev, M.
name: Miranda, J. M.
name: Mirzoyan, R.
name: Molina, E.
name: Moralejo, A.
name: Morcuende, D.
name: Moreno, V.
name: Moretti, E.
name: Neustroev, V.
name: Nigro, C.
name: Nilsson, K.
name: Nishijima, K.
name: Noda, K.
name: Nozaki, S.
name: Ohtani, Y.
name: Oka, T.
name: Otero-Santos, J.
name: Paiano, S.
name: Palatiello, M.
name: Paneque, D.
name: Paoletti, R.
name: Paredes, J. M.
name: Pavletić, L.
name: Peñil, P.
name: Perennes, C.
name: Persic, M.
name: Moroni, P. G. Prada
name: Prandini, E.
name: Priyadarshi, C.
name: Puljak, I.
name: Ribó, M.
name: Rico, J.
name: Righi, C.
name: Rugliancich, A.
name: Saha, L.
name: Sahakyan, N.
name: Saito, T.
name: Sakurai, S.
name: Satalecka, K.
name: Saturni, F. G.
name: Schmidt, K.
name: Schweizer, T.
name: Sitarek, J.
name: Šnidarić, I.
name: Sobczynska, D.
name: Spolon, A.
name: Stamerra, A.
name: Strom, D.
name: Strzys, M.
name: Suda, Y.
name: Surić, T.
name: Takahashi, M.
name: Tavecchio, F.
name: Temnikov, P.
name: Terzić, T.
name: Teshima, M.
name: Tosti, L.
name: Truzzi, S.
name: Tutone, A.
name: Ubach, S.
name: van Scherpenberg, J.
name: Vanzo, G.
name: Acosta, M. Vazquez
name: Ventura, S.
name: Verguilov, V.
name: Vigorito, C. F.
name: Vitale, V.
name: Vovk, I.
name: Will, M.
name: Wunderlich, C.
name: Zarić, D.
name: Collaboration, FACT
name: :
name: Baack, D.
name: Balbo, M.
name: Biederbeck, N.
name: Biland, A.
name: Bretz, T.
name: Buss, J.
name: Dorner, D.
name: Eisenberger, L.
name: Elsaesser, D.
name: Hildebrand, D.
name: Iotov, R.
name: Mannheim, K.
name: Neise, D.
name: Noethe, M.
name: Paravac, A.
name: Rhode, W.
name: Schleicher, B.
name: Sliusar, V.
name: Walter, R.
name: groups, Other
name: Collaborations
name: :
name: D'Ammando, F.
name: Horan, D.
name: Lien, A. Y.
name: Baloković, M.
name: Madejski, G. M.
name: Perri, M.
name: Verrecchia, F.
name: Leto, C.
name: Lähteenmäki, A.
name: Tornikoski, M.
name: Ramakrishnan, V.
name: Järvelä, E.
name: Vera, R. J. C.
name: Villata, M.
name: Raiteri, C. M.
name: Gupta, A. C.
name: Pandey, A.
name: Fuentes, A.
name: Agudo, I.
name: Casadio, C.
name: Semkov, E.
name: Ibryamov, S.
name: Marchini, A.
name: Bachev, R.
name: Strigachev, A.
name: Ovcharov, E.
name: Bozhilov, V.
name: Valcheva, A.
name: Zaharieva, E.
name: Damljanovic, G.
name: Vince, O.
name: Larionov, V. M.
name: Borman, G. A.
name: Grishina, T. S.
name: Hagen-Thorn, V. A.
name: Kopatskaya, E. N.
name: Larionova, E. G.
name: Larionova, L. V.
name: Morozova, D. A.
name: Nikiforova, A. A.
name: Savchenko, S. S.
name: Troitskiy, I. S.
name: Troitskaya, Y. V.
name: Vasilyev, A. A.
name: Merkulova, O. A.
name: Chen, W. P.
name: Samal, M.
name: Lin, H. C.
name: Moody, J. W.
name: Sadun, A. C.
name: Jorstad, S. G.
name: Marscher, A. P.
name: Weaver, Z. R.
name: Feige, M.
name: Kania, J.
name: Kopp, M.
name: Kunkel, L.
name: Reinhart, D.
name: Scherbantin, A.
name: Schneider, L.
name: Lorey, C.
name: Acosta-Pulido, J. A.
name: Carnerero, M. I.
name: Carosati, D.
name: Kurtanidze, S. O.
name: Kurtanidze, O. M.
name: Nikolashvili, M. G.
name: Chanishvili, R. G.
name: Chigladze, R. A.
name: Ivanidze, R. Z.
name: Kimeridze, G. N.
name: Sigua, L. A.
name: Joner, M. D.
name: Spencer, M.
name: Giroletti, M.
name: Marchili, N.
name: Righini, S.
name: Rizzi, N.
name: Bonnoli, G.
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: 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 Metsähovi. 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 &gt; 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.
description: 38 pages, 23 figures, accepted for publication in Astronomy and Astrophysics. Corresponding authors: Axel Arbet-Engels, David Paneque