Testing two-component models on very-high-energy gamma-ray emitting BL Lac objects
Abstract
Context. It has become evident that one-zone synchrotron self-Compton models are not always adequate for very-high-energy (VHE) gamma-ray emitting blazars. While two-component models are performing better, they are difficult to constrain due to the large number of free parameters. Aims. In this work, we make a first attempt to take into account the observational constraints from Very Long Baseline Interferometry (VLBI) data, long-term light curves (radio, optical, and X-rays) and optical polarisation to limit the parameter space for a two-component model and test if it can still reproduce the observed spectral energy distribution (SED) of the blazars. Methods. We selected five TeV BL Lac objects based on the availability of VHE gamma-ray and optical polarisation data. We collected constraints for the jet parameters from VLBI observations. We evaluated the contributions of the two components to the optical flux by means of decomposition of long-term radio and optical light curves as well as modeling of the optical polarisation variability of the objects. We selected eight epochs for these five objects, based on the variability observed at VHE gamma rays, for which we constructed the SEDs that we then modeled with a two-component model. Results. We found parameter sets which can reproduce the broadband SED of the sources in the framework of two-component models considering all available observational constraints from VLBI observations. Moreover, the constraints obtained from the long-term behavior of the sources in the lower energy bands could be used to determine the region where the emission in each band originates. Finally, we attempted to use optical polarisation data to shed new light on the behavior of the two components in the optical band. Our observationally constrained two zone model allows explanation of the entire SED from radio to VHE with two co-located emission regions.
Cite
@article{arxiv.2006.04493,
title = {Testing two-component models on very-high-energy gamma-ray emitting BL Lac objects},
author = {MAGIC Collaboration and V. A. Acciari and S. Ansoldi and L. A. Antonelli and A. Arbet Engels and D. Baack and A. Babić and B. Banerjee and U. Barres de Almeida and J. A. Barrio and J. Becerra González and W. Bednarek and L. Bellizzi and E. Bernardini and A. Berti and J. Besenrieder and W. Bhattacharyya and C. Bigongiari and A. Biland and O. Blanch and G. Bonnoli and Ž. Bošnjak and G. Busetto and R. Carosi and G. Ceribella and M. Cerruti and Y. Chai and A. Chilingarian and S. Cikota and S. M. Colak and U. Colin and E. Colombo and J. L. Contreras and J. Cortina and S. Covino and G. D'Amico and V. D'Elia and P. Da Vela and F. Dazzi and A. De Angelis and B. De Lotto and M. Delfino and J. Delgado and D. Depaoli and F. Di Pierro and L. Di Venere and E. Do Souto Espiñeira and D. Dominis Prester and A. Donini and D. Dorner and M. Doro and D. Elsaesser and V. Fallah Ramazani and A. Fattorini and G. Ferrara and L. Foffano and M. V. Fonseca and L. Font and C. Fruck and S. Fukami and R. J. García López and M. Garczarczyk and S. Gasparyan and M. Gaug and N. Giglietto and F. Giordano and P. Gliwny and N. Godinović and D. Green and D. Hadasch and A. Hahn and J. Herrera and J. Hoang and D. Hrupec and M. Hütten and T. Inada and S. Inoue and K. Ishio and Y. Iwamura and L. Jouvin and Y. Kajiwara and M. Karjalainen and D. Kerszberg and Y. Kobayashi and H. Kubo and J. Kushida and A. Lamastra and D. Lelas and F. Leone and E. Lindfors and S. Lombardi and F. Longo and M. López and R. López-Coto and A. López-Oramas and S. Loporchio and B. Machado de Oliveira Fraga and C. Maggio and P. Majumdar and M. Makariev and M. Mallamaci and G. Maneva and M. Manganaro and K. Mannheim and L. Maraschi and M. Mariotti and M. Martínez and D. Mazin and S. Mender and S. Mićanović and D. Miceli and T. Miener and M. Minev and J. M. Miranda and R. Mirzoyan and E. Molina and A. Moralejo and D. Morcuende and V. Moreno and E. Moretti and P. Munar-Adrover and V. Neustroev and C. Nigro and K. Nilsson and D. Ninci and K. Nishijima and K. Noda and L. Nogués and S. Nozaki and Y. Ohtani and T. Oka and J. Otero-Santos and M. Palatiello and D. Paneque and R. Paoletti and J. M. Paredes and L. Pavletić and P. Peñil and M. Peresano and M. Persic and P. G. Prada Moroni and E. Prandini and I. Puljak and W. Rhode and M. Ribó and J. Rico and C. Righi and A. Rugliancich and L. Saha and N. Sahakyan and T. Saito and S. Sakurai and K. Satalecka and B. Schleicher and K. Schmidt and T. Schweizer and J. Sitarek and I. Šnidarić and D. Sobczynska and A. Spolon and A. Stamerra and D. Strom and M. Strzys and Y. Suda and T. Surić and M. Takahashi and F. Tavecchio and P. Temnikov and T. Terzić and M. Teshima and N. Torres-Albà and L. Tosti and J. van Scherpenberg and G. Vanzo and M. Vazquez Acosta and S. Ventura and V. Verguilov and C. F. Vigorito and V. Vitale and I. Vovk and M. Will and D. Zarić and M. Nievas-Rosillo and C. Arcaro and F. D' Ammando and F. de Palma and M. Hodges and T. Hovatta and S. Kiehlmann and W. Max-Moerbeck and A. C. S. Readhead and R. Reeves and L. Takalo and R. Reinthal and J. Jormanainen and F. Wierda and S. M. Wagner and A. Berdyugin and A. Nabizadeh and N. Talebpour Sheshvan and A. Oksanen and R. Bachev and A. Strigachev and P. Kehusmaa},
journal= {arXiv preprint arXiv:2006.04493},
year = {2020}
}