Details

Autor(en) / Beteiligte

• Acciari, V A
• Antonelli, L A
• Barrio, J A
• Bellizzi, L
• Bernardini, E
• Besenrieder, J
• Bhattacharyya, W
• Bošnjak, Ž
• Busetto, G
• Ceribella, G
• Cerruti, M
• Contreras, J L
• Covino, S
• D’Elia, V
• Da Vela, P
• Delfino, M
• Delgado Mendez, C
• Di Girolamo, T
• Di Pierro, F
• Di Venere, L
• Doro, M
• Fallah Ramazani, V
• Ferrara, G
• Font, L
• Fukami, S
• García López, R J
• Giglietto, N
• Gliwny, P
• Godinović, N
• Green, J G
• Hadasch, D
• Hahn, A
• Herrera, J
• Hoang, J
• Hütten, M
• Inada, T
• Inoue, S
• Ishio, K
• Kajiwara, Y
• Karjalainen, M
• Lamastra, A
• Lombardi, S
• Loporchio, S
• Maggio, C
• Makariev, M
• Mallamaci, M
• Manganaro, M
• Maraschi, L
• Mariotti, M
• Miceli, D
• Minev, M
• Miranda, J M
• Moralejo, A
• Morcuende, D
• Moreno, V
• Neustroev, V
• Nilsson, K
• Ninci, D
• Ohtani, Y
• Palatiello, M
• Persic, M
• Prada Moroni, P G
• Ribó, M
• Rico, J
• Righi, C
• Rugliancich, A
• Saha, L
• Sahakyan, N
• Sakurai, S
• Satalecka, K
• Schleicher, B
• Schmidt, K
• Schweizer, T
• Sitarek, J
• Strom, D
• Strzys, M
• Surić, T
• Terzić, T
• Torres-Albà, N
• Ventura, S
• Verguilov, V
• Vigorito, C F
• Vovk, I
• Zarić, D
• Baack, D
• Biederbeck, N
• Biland, A
• Bretz, T
• Bruegge, K
• Buss, J
• Dorner, D
• Elsaesser, D
• Neise, D
• Neronov, A
• Theissen, F
• Valverde, J
• Perri, M
• Marscher, A P
• Järvelä, E
• Righini, S

Titel

Multiwavelength variability and correlation studies of Mrk 421 during historically low X-ray and γ-ray activity in 2015–2016

Ist Teil von

• Monthly notices of the Royal Astronomical Society, 2021-06, Vol.504 (1), p.1427-1451

Ort / Verlag

Oxford University Press

Erscheinungsjahr

2021

Quelle

EZB Free E-Journals

Beschreibungen/Notizen

• 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 Metsähovi, 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 × 10−12 ph cm−2 s−1) and in the 2–10 keV (X-ray) band (F$_{2-10\, \mathrm{keV}}\lt 3.6\times 10^{-11}$ 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) γ-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 $43^{+9}_{-6}$ 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.