Acciari, V. A., Ansoldi, S., Antonelli, L. A., Arbet Engels, A., Baack, D., Babić, A., Banerjee, B., Barres de Almeida, U., Barrio, J. A., Becerra González, J., Bednarek, W., Bellizzi, L., Bernardini, E., Berti, A., Besenrieder, J., Bhattacharyya, W., Bigongiari, C., Biland, A., … Kehusmaa, P. (2020). Testing two-component models on very high-energy gamma-ray-emitting BL Lac objects. Astronomy & Astrophysics, 640, A132. https://doi.org/10.1051/0004-6361/202037811
Testing two-component models on very high-energy gamma-ray-emitting BL Lac objects
|Author:||Acciari, V. A.1,2; Ansoldi, S.3,4,5,6,7,8; Antonelli, L. A.9;|
1Inst Astrofis Canarias, E-38200 San Cristobal la Laguna, Spain.
2Univ La Laguna, Dept Astrofis, E-38206 Tenerife, Spain.
3Univ Udine, I-33100 Udine, Italy.
4INFN Trieste, I-33100 Udine, Italy.
5Univ Tokyo, Japanese MAGIC Consortium ICRR, Chiba 2778582, Japan.
6Kyoto Univ, Dept Phys, Kyoto 6068502, Japan.
7Tokai Univ, Hiratsuka, Kanagawa 2591292, Japan.
8RIKEN, Wako, Saitama 3510198, Japan.
9Natl Inst Astrophys INAF, I-00136 Rome, Italy.
10Swiss Fed Inst Technol, CH-8093 Zurich, Switzerland.
11Tech Univ Dortmund, D-44221 Dortmund, Germany.
12Univ Rijeka, Dept Phys, Croatian Consortium, Rijeka 51000, Croatia.
13Univ Split, FESB, Split 21000, Croatia.
14Univ Zagreb, FER, Zagreb 10000, Croatia.
15Univ Osijek, Osijek 31000, Croatia.
16Rudjer Boskovic Inst, Zagreb 10000, Croatia.
17HBNI, Saha Inst Nucl Phys, 1 AF Bidhannagar,Sect 1, Kolkata 700064, India.
18URCA, Ctr Brasileiro Pesquisas Fis CBPF, BR-22290180 Rio De Janeiro, RJ, Brazil.
19Univ Complutense Madrid, IPARCOS Inst, E-28040 Madrid, Spain.
20Univ Complutense Madrid, EMFTEL Dept, E-28040 Madrid, Spain.
21Univ Lodz, Fac Phys & Appl Informat, Dept Astrophys, PL-90236 Lodz, Poland.
22Univ Siena, I-53100 Siena, Italy.
23INFN Pisa, I-53100 Siena, Italy.
24Deutsch Elektronen Synchrotron DESY, D-15738 Zeuthen, Germany.
25Univ Padua, I-35131 Padua, Italy.
26Ist Nazl Fis Nucl, I-35131 Padua, Italy.
27Ist Nazl Fis Nucl INFN, I-00044 Rome, Italy.
28Max Planck Inst Phys & Astrophys, D-80805 Munich, Germany.
29Barcelona Inst Sci & Technol BIST, Inst Fis Altes Energies IFAE, E-08193 Bellaterra, Barcelona, Spain.
30INFN Pisa, I-56126 Pisa, Italy.
31Univ Pisa, I-56126 Pisa, Italy.
32Univ Barcelona, IEEC UB, ICCUB, E-08028 Barcelona, Spain.
33NAS RA, Armenian Consortium ICRANet Armenia, A Alikhanyan Natl Lab, Yerevan, Armenia.
34Ctr Invest Energet Medioambientales & Tecnol, E-28040 Madrid, Spain.
35Univ Innsbruck, Innsbruck, Austria.
36Port Informacio Cient PIC, Bellaterra 08193, Barcelona, Spain.
37Univ Wurzburg, D-97074 Wurzburg, Germany.
38Univ Turku, Finnish MAGIC Consortium, Finnish Ctr Astron, ESO FINCA, Turku 20014, Finland.
39Univ Oulu, Astron Res Unit, Oulu 90014, Finland.
40Univ Autonoma Barcelona, Dept Fis, E-08193 Bellaterra, Spain.
41Univ Autonoma Barcelona, CERES IEEC, E-08193 Bellaterra, Spain.
42Univ Trieste, Dipartimento Fis, I-34127 Trieste, Italy.
43Bulgarian Acad Sci, Inst Nucl Res & Nucl Energy, Sofia 1784, Bulgaria.
44Univ Bologna, INAF Trieste, Bologna, Italy.
45Univ Bologna, Dept Phys & Astron, Bologna, Italy.
46North West Univ, Ctr Space Res, ZA-2520 Potchefstroom, South Africa.
47INAF Osservatorio Astron Padova, Vicolo Osservatorio 5, I-35122 Padua, Italy.
48Ist RadioAstron, I-40129 Bologna, Italy.
49Ist Nazl Fis Nucl, Sez Torino, I-10125 Turin, Italy.
50CALTECH, Owens Valley Radio Observ, Pasadena, CA 91125 USA.
51Univ Turku, Finnish Ctr Astron, ESO FINCA, Turku 20014, Finland.
52Aalto Univ, Metsahovi Radio Observ, Metshovintie 114, Kylmala 02540, Finland.
53Fdn Res & Technol Hellas, Inst Astrophys, Iraklion 71110, Greece.
54Univ Crete, Dept Phys, Iraklion 70013, Greece.
55Univ Chile, Dept Astron, Camino Observ 1515, Santiago, Chile.
56Univ Concepcion, Dept Astron, Concepcion, Chile.
57Univ Turku, Dept Phys & Astron, Turku 20014, Finland.
58Hankasalmi Observ, Murtoistentie 116-124, Hankasalmi 41500, Finland.
59Bulgarian Acad Sci, Inst Astron, Sofia 1784, Bulgaria.
60Bulgarian Acad Sci, NAO, Sofia 1784, Bulgaria.
61Harlingten New Mexico Observ, Mayhill, NM USA.
|Online Access:||PDF Full Text (PDF, 5.8 MB)|
|Persistent link:|| http://urn.fi/urn:nbn:fi-fe2020120499498
|Publish Date:|| 2020-12-04
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 perform better, they are difficult to constrain due to the large number of free parameters.
Aims: In this work, we make a first attempt at taking 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 whether or not 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 modelling 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 modelled 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 behaviour of the sources in the lower energy bands could be used to determine the region where the emission in each band originates. Finally, we attempt to use optical polarisation data to shed new light on the behaviour of the two components in the optical band. Our observationally constrained two-component model allows explanation of the entire SED from radio to VHE with two co-located emission regions.
Astronomy and astrophysics
|Type of Publication:||
A1 Journal article – refereed
|Field of Science:||
115 Astronomy and space science
VFR and EL were supported by Academy of Finland projects 317636 and 320045. We would like to thank the Instituto de Astrofísica de Canarias for the excellent working conditions at the Observatorio del Roque de los Muchachos in La Palma. The financial support of the German BMBF and MPG; the Italian INFN and INAF; the Swiss National Fund SNF; the ERDF under the Spanish MINECO (FPA2017-87859-P, FPA2017-85668-P, FPA2017-82729- C6-2-R, FPA2017-82729-C6-6-R, FPA2017-82729-C6-5-R, AYA2015-71042-P, AYA2016-76012-C3-1-P, ESP2017-87055-C2-2-P, FPA2017-90566-REDC); the Indian Department of Atomic Energy; the Japanese ICRR, the University of Tokyo, JSPS, and MEXT; the Bulgarian Ministry of Education and Science, National RI Roadmap Project DO1-268/16.12.2019 and the Academy of Finland grant nr. 320045 is gratefully acknowledged. This work was also supported by the Spanish Centro de Excelencia “Severo Ochoa” SEV-2016-0588 and SEV-2015-0548, the Unidad de Excelencia “María de Maeztu” MDM-2014-0369 and the “la Caixa” Foundation (fellowship LCF/BQ/PI18/11630012), by the Croatian Science Foundation (HrZZ) Project IP-2016-06-9782 and the University of Rijeka Project 22.214.171.124.02, by the DFG Collaborative Research Centers SFB823/C4 and SFB876/C3, the Polish National Research Centre grant UMO-2016/22/M/ST9/00382 and by the Brazilian MCTIC, CNPq and FAPERJ. The Fermi-LAT Collaboration acknowledges generous ongoing support from a number of agencies and institutes that have supported both the development and the operation of the LAT as well as scientific data analysis. These include the National Aeronautics and Space Administration and the Department of Energy in the United States, the Commissariat à l’Energie Atomique and the Centre National de la Recherche Scientifique/Institut National de Physique Nucléaire et de Physique des Particules in France, the Agenzia Spaziale Italiana and the Istituto Nazionale di Fisica Nucleare in Italy, the Ministry of Education, Culture, Sports, Science and Technology (MEXT), High Energy Accelerator Research Organization (KEK) and Japan Aerospace Exploration Agency (JAXA) in Japan, and the K. A. Wallenberg Foundation, the Swedish Research Council and the Swedish National Space Board in Sweden. Additional support for science analysis during the operations phase is gratefully acknowledged from the Istituto Nazionale di Astrofisica in Italy and the Centre National d’Études Spatiales in France. This work performed in part under DOE Contract DE-AC02-76SF00515. Part of this work is based on observations made with the Nordic Optical Telescope, operated by the Nordic Optical Telescope Scientific Association at the Observatorio del Roque de los Muchachos, La Palma, Spain, of the Instituto de Astrofisica de Canarias. We acknowledge the support from the Bulgarian NSF through grants DN 18-1220 13/2017, DN 18-10/2017, KP-06-H28/3 (2018) and KP-06-PN38/1 (2019).
This research has made use of data from the OVRO 40-m monitoring program which is supported in part by NASA grants NNX08AW31G, NNX11A043G, and NNX14AQ89G and NSF grants AST-0808050 and AST-1109911. This research has made use of data from the MOJAVE database that is maintained by the MOJAVE team (Lister et al. 2019). Part of this work is based on archival data, software, or online services provided by the Space Science Data Centre – ASI. This research has made use of data and/or software provided by the High Energy Astrophysics Science Archive Research Center (HEASARC), which is a service of the Astrophysics Science Division at NASA/GSFC and the High Energy Astrophysics Division of the Smithsonian Astrophysical Observatory.
© ESO 2020.