Dissecting the long-term emission behaviour of the BL Lac object Mrk 421
Files
Published version
Date
2017-12-21
Authors
Carnerero, M.I.
Raiteri, C.M.
Villata, M.
Acosta-Pulido, J.A.
Larionov, V.M.
Smith, P.S.
D'Ammando, F.
Agudo, Ivan
Arévalo, M.J.
Bachev, R.
Version
Accepted manuscript
OA Version
Citation
MI Carnerero, CM Raiteri, M Villata, JA Acosta-Pulido, VM Larionov, PS Smith, F D'Ammando, I Agudo, MJ Arévalo, R Bachev, J Barnes, S Boeva, V Bozhilov, D Carosati, C Casadio, WP Chen, G Damljanovic, E Eswaraiah, E Forné, G Gantchev, JL Gómez, PA González-Morales, AB Griñón-Marín, TS Grishina, M Holden, S Ibryamov, MD Joner, B Jordan, SG Jorstad, M Joshi, EN Kopatskaya, E Koptelova, OM Kurtanidze, SO Kurtanidze, EG Larionova, LV Larionova, G Latev, C Lázaro, R Ligustri, HC Lin, AP Marscher, C Martínez-Lombilla, B McBreen, B Mihov, SN Molina, JW Moody, DA Morozova, MG Nikolashvili, K Nilsson, E Ovcharov, C Pace, N Panwar, A Pastor Yabar, RL Pearson, F Pinna, C Protasio, N Rizzi, FJ Redondo-Lorenzo, G Rodríguez-Coira, JA Ros, AC Sadun, SS Savchenko, E Semkov, L Slavcheva-Mihova, N Smith, A Strigachev, Yu V Troitskaya, IS Troitsky, AA Vasilyev, O Vince. 2017. "Dissecting the long-term emission behaviour of the BL Lac object Mrk 421." Monthly Notices of the Royal Astronomical Society, v. 472, Issue 4, pp. 3789 - 3804.
Abstract
We report on long-term multiwavelengthmonitoring of blazar Mrk 421 by the GLAST-AGILE
Support Program of the Whole Earth Blazar Telescope (GASP-WEBT) collaboration and
Steward Observatory, and by the Swift and Fermi satellites. We study the source behaviour in
the period 2007–2015, characterized by several extreme flares. The ratio between the optical,
X-ray and γ -ray fluxes is very variable. The γ -ray flux variations show a fair correlation with
the optical ones starting from 2012.We analyse spectropolarimetric data and find wavelengthdependence
of the polarization degree (P), which is compatible with the presence of the
host galaxy, and no wavelength dependence of the electric vector polarization angle (EVPA).
Optical polarimetry shows a lack of simple correlation between P and flux and wide rotations of
the EVPA.We build broad-band spectral energy distributions with simultaneous near-infrared
and optical data from the GASP-WEBT and ultraviolet and X-ray data from the Swift satellite.
They show strong variability in both flux and X-ray spectral shape and suggest a shift of
the synchrotron peak up to a factor of ∼50 in frequency. The interpretation of the flux and
spectral variability is compatible with jet models including at least two emitting regions that
can change their orientation with respect to the line of sight.
Description
License
This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2017 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.