Multiwavelength variability and correlation studies of Mrk 421 during historically low X-ray and gamma-ray activity in 2015-2016
Articolo
Data di Pubblicazione:
2021
Abstract:
We report a characterization of the multiband flux variability and correlations of the nearby (z = 0.031) blazar Markarian 421 (Mrk 421) using data from Metsahovi, Swift, Fermi-LAT, MAGIC, FACT, and other collaborations and instruments from 2014 November till 2016 June. Mrk 421 did not show any prominent flaring activity, but exhibited periods of historically low activity above 1 TeV (F->1 TeV < 1.7 x 10(-12) ph cm(-2) s(-1)) and in the 2-10 keV (X-ray) band (F2-10 keV < 3.6 x 10(-11) erg cm(-2) s(-1)), during which the Swift-BAT data suggest an additional spectral component beyond the regular synchrotron emission. The highest flux variability occurs in X-rays and very high-energy (E > 0.1 TeV) gamma-rays, which, despite the low activity, show a significant positive correlation with no time lag. The HRkeV and HRTeV show the harder-when-brighter trend observed in many blazars, but the trend flattens at the highest fluxes, which suggests a change in the processes dominating the blazar variability. Enlarging our data set with data from years 2007 to 2014, we measured a positive correlation between the optical and the GeV emission over a range of about 60 d centred at time lag zero, and a positive correlation between the optical/GeV and the radio emission over a range of about 60 d centred at a time lag of 43(-6)(+9) d. This observation is consistent with the radio-bright zone being located about 0.2 parsec downstream from the optical/GeV emission regions of the jet. The flux distributions are better described with a lognormal function in most of the energy bands probed, indicating that the variability in Mrk 421 is likely produced by a multiplicative process.
Tipologia CRIS:
03A-Articolo su Rivista
Keywords:
radiation mechanisms: non-thermal; methods: data analysis; methods: observational; galaxies: active; BL Lacertae objects: individual: Mrk 421
Elenco autori:
Acciari, VA; Ansoldi, S; Antonelli, LA; Asano, K; Babic, A; Banerjee, B; Baquero, A; de Almeida, UB; Barrio, JA; Gonzalez, JB; Bednarek, W; Bellizzi, L; Bernardini, E; Bernardos, M; Berti, A; Besenrieder, J; Bhattacharyya, W; Bigongiari, C; Blanch, O; Bonnoli, G; Bosnjak, Z; Busetto, G; Carosi, R; Ceribella, G; Cerruti, M; Chai, Y; Chilingarian, A; Cikota, S; Colak, SM; Colombo, E; Contreras, JL; Cortina, J; Covino, S; D'Amico, G; D'Elia, V; Da Vela, P; Dazzi, F; De Angelis, A; De Lotto, B; Delfino, M; Delgado, J; Mendez, CD; Depaoli, D; Di Girolamo, T; Di Pierro, F; Di Venere, L; Neira, EDE; Prester, DD; Donini, A; Doro, M; Ramazani, VF; Fattorini, A; Ferrara, G; Foffano, L; Fonseca, MV; Font, L; Fruck, C; Fukami, S; Lopez, RJG; Garczarczyk, M; Gasparyan, S; Gaug, M; Giglietto, N; Giordano, F; Gliwny, P; Green, JG; Green, D; Hadasch, D; Hahn, A; Heckmann, L; Herrera, J; Hoang, J; Hrupec, D; Hutten, M; Inada, T; Inoue, S; Ishio, K; Iwamura, Y; Jormanainen, J; Jouvin, L; Kajiwara, Y; Karjalainen, M; Kerszberg, D; Kobayashi, Y; Kubo, H; Kushida, J; Lamastra, A; Lelas, D; Leone, F; Lindfors, E; Lombardi, S; Longo, F; Lopez, M; Lopez-Coto, R; Lopez-Oramas, A; Loporchio, S; Fraga, BMD; Maggio, C; Majumdar, P; Makariev, M; Mallamaci, M; Maneva, G; Manganaro, M; Maraschi, L; Mariotti, M; Martinez, M; Mazin, D; Mender, S; Micanovic, S; Miceli, D; Miener, T; Minev, M; Miranda, JM; Mirzoyan, R; Molina, E; Moralejo, A; Morcuende, D; Moreno, V; Moretti, E; Munar-Adrover, P; Neustroev, V; Nigro, C; Nilsson, K; Ninci, D; Nishijima, K; Noda, K; Nozaki, S; Ohtani, Y; Oka, T; Otero-Santos, J; Palatiello, M; Paneque, D; Paoletti, R; Paredes, JM; Pavletic, L; Penil, P; Perennes, C; Persic, M; Moroni, PGP; Prandini, E; Priyadarshi, C; Puljak, I; Rhode, W; Ribo, M; Rico, J; Righi, C; Rugliancich, A; Saha, L; Sahakyan, N; Saito, T; Sakurai, S; Satalecka, K; Schleicher, B; Schmidt, K; Schweizer, T; Sitarek, J; Snidaric, I; Sobczynska, D; Spolon, A; Stamerra, A; Strom, D; Strzys, M; Suda, Y; Suric, T; Takahashi, M; Tavecchio, F; Temnikov, P; Terzic, T; Teshima, M; Torres-Alba, N; Tosti, L; Truzzi, S; van Scherpenberg, J; Vanzo, G; Acosta, MV; Ventura, S; Verguilov, V; Vigorito, CF; Vitale, V; Vovk, I; Will, M; Zaric, D; Arbet-Engels, A; Baack, D; Balbo, M; Beck, M; Biederbeck, N; Biland, A; Bretz, T; Bruegge, K; Buss, J; Dorner, D; Elsaesser, D; Hildebrand, D; Iotov, R; Klinger, M; Mannheim, K; Neise, D; Neronov, A; Noethe, M; Paravac, A; Rhode, W; Sliusar, V; Theissen, F; Walter, R; Valverde, J; Horan, D; Giroletti, M; Perri, M; Verrecchia, F; Leto, C; Sadun, AC; Moody, JW; Joner, M; Marscher, AP; Jorstad, SG; Lahteenmaki, A; Tornikoski, M; Ramakrishnan, V; Jarvela, E; Vera, RJC; Righini, S; Lien, AY
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