Investigation of the correlation patterns and the Compton dominance variability of Mrk 421 in 2017
Articolo
Data di Pubblicazione:
2021
Abstract:
Aims. We present a detailed characterisation and theoretical interpretation of the broadband emission of the paradigmatic TeV blazar Mrk 421, with a special focus on the multi-band flux correlations.Methods. The dataset has been collected through an extensive multi-wavelength campaign organised between 2016 December and 2017 June. The instruments involved are MAGIC, FACT, Fermi-LAT, Swift, GASP-WEBT, OVRO, Medicina, and Metsahovi. 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.Results. 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 for 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. The peak frequency of the synchrotron bump varies by two orders of magnitude throughout the campaign. Our multi-band correlation study also hints at an anti-correlation between UV-optical and X-ray at a significance higher than 3 sigma. A VHE flare observed on MJD 57788 (2017 February 4) shows gamma-ray variability on multi-hour timescales, with a factor ten 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, from gamma(min)' = 2 x 10(4) to gamma(max)' = 6 x 10(5).
Tipologia CRIS:
03A-Articolo su Rivista
Keywords:
galaxies: active; BL Lacertae objects: individual: Mrk 421; radiation mechanisms: non-thermal
Elenco autori:
V. A. Acciari; S. Ansoldi; L. A. Antonelli; A. Arbet Engels; M. Artero; K. Asano; A. Babi??; A. Baquero; U. Barres de Almeida; J. A. Barrio; I. Batkovi??; J. Becerra Gonz??lez; W. Bednarek; L. Bellizzi; E. Bernardini; M. Bernardos; A. Berti; J. Besenrieder; W. Bhattacharyya; C. Bigongiari; O. Blanch; ??. Bo??njak; G. Busetto; R. Carosi; G. Ceribella; M. Cerruti; Y. Chai; A. Chilingarian; S. Cikota; S. M. Colak; E. Colombo; J. L. Contreras; J. Cortina; S. Covino; G. D???Amico; V. D???Elia; P. Da Vela; F. Dazzi; A. De Angelis; B. De Lotto; M. Delfino; J. Delgado; C. Delgado Mendez; D. Depaoli; F. Di Pierro; L. Di Venere; E. Do Souto Espi??eira; D. Dominis Prester; A. Donini; M. Doro; V. Fallah Ramazani; A. Fattorini; G. Ferrara; M. V. Fonseca; L. Font; C. Fruck; S. Fukami; R. J. Garc??a L??pez; M. Garczarczyk; S. Gasparyan; M. Gaug; N. Giglietto; F. Giordano; P. Gliwny; N. Godinovi??; J. G. Green; D. Green; D. Hadasch; A. Hahn; L. Heckmann; J. Herrera; J. Hoang; D. Hrupec; M. H??tten; T. Inada; S. Inoue; K. Ishio; Y. Iwamura; I. Jim??nez; J. Jormanainen; L. Jouvin; Y. Kajiwara; M. Karjalainen; D. Kerszberg; Y. Kobayashi; H. Kubo; J. Kushida; A. Lamastra; D. Lelas; F. Leone; E. Lindfors; S. Lombardi; F. Longo; R. L??pez-Coto; M. L??pez-Moya; A. L??pez-Oramas; S. Loporchio; B. Machado de Oliveira Fraga; C. Maggio; P. Majumdar; M. Makariev; M. Mallamaci; G. Maneva; M. Manganaro; L. Maraschi; M. Mariotti; M. Mart??nez; D. Mazin; S. Menchiari; S. Mender; S. Mi??anovi??; D. Miceli; T. Miener; M. Minev; J. M. Miranda; R. Mirzoyan; E. Molina; A. Moralejo; D. Morcuende; V. Moreno; E. Moretti; V. Neustroev; C. Nigro; K. Nilsson; K. Nishijima; K. Noda; S. Nozaki; Y. Ohtani; T. Oka; J. Otero-Santos; S. Paiano; M. Palatiello; D. Paneque; R. Paoletti; J. M. Paredes; L. Pavleti??; P. Pe??il; C. Perennes; M. Persic; P. G. Prada Moroni; E. Prandini; C. Priyadarshi; I. Puljak; M. Rib??; J. Rico; C. Righi; A. Rugliancich; L. Saha; N. Sahakyan; T. Saito; S. Sakurai; K. Satalecka; F. G. Saturni; K. Schmidt; T. Schweizer; J. Sitarek; I. ??nidari??; D. Sobczynska; A. Spolon; A. Stamerra; D. Strom; M. Strzys; Y. Suda; T. Suri??; M. Takahashi; F. Tavecchio; P. Temnikov; T. Terzi??; M. Teshima; L. Tosti; S. Truzzi; A. Tutone; S. Ubach; J. van Scherpenberg; G. Vanzo; M. Vazquez Acosta; S. Ventura; V. Verguilov; C. F. Vigorito; V. Vitale; I. Vovk; M. Will; C. Wunderlich; D. Zari??; D. Baack; M. Balbo; N. Biederbeck; A. Biland; T. Bretz; J. Buss; D. Dorner; L. Eisenberger; D. Elsaesser; D. Hildebrand; R. Iotov; K. Mannheim; D. Neise; M. Noethe; A. Paravac; W. Rhode; B. Schleicher; V. Sliusar; R. Walter; F. D???Ammando; D. Horan; A. Y. Lien; M. Balokovi??; G. M. Madejski; M. Perri; F. Verrecchia; C. Leto; A. L??hteenm??ki; M. Tornikoski; V. Ramakrishnan; E. J??rvel??; R. J. C. Vera; W. Chamani; M. Villata; C. M. Raiteri; A. C. Gupta; A. Pandey; A. Fuentes; I. Agudo; C. Casadio; E. Semkov; S. Ibryamov; A. Marchini; R. Bachev; A. Strigachev; E. Ovcharov; V. Bozhilov; A. Valcheva; E. Zaharieva; G. Damljanovic; O. Vince; V. M. Larionov; G. A. Borman; T. S. Grishina; V. A. Hagen-Thorn; E. N. Kopatskaya; E. G. Larionova; L. V. Larionova; D. A. Morozova; A. A. Nikiforova; S. S. Savchenko; I. S. Troitskiy; Y. V. Troitskaya; A. A. Vasilyev; O. A. Merkulova; W. P. Chen; M. Samal; H. C. Lin; J. W. Moody; A. C. Sadun; S. G. Jorstad; A. P. Marscher; Z. R. Weaver; M. Feige; J. Kania; M. Kopp; L. Kunkel; D. Reinhart; A. Scherbantin; L. Schneider; C. Lorey; J. A. Acosta-Pulido; M. I. Carnerero; D. Carosati; S. O. Kurtanidze; O. M. Kurtanidze; M. G. Nikolashvili; R. A. Chigladze; R. Z. Ivanidze; G. N. Kimeridze; L. A. Sigua; M. D. Joner; M. Spencer; M. Giroletti; N. Marchili; S. Righini; N. Rizzi; G. Bonnoli
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