Unraveling the complex behavior of Mrk 421 with simultaneous X-Ray and VHE observations during an extreme flaring activity in 2013 April
|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.
26INFN, 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.
30Univ Pisa, I-56126 Pisa, Italy.
31INFN Pisa, I-56126 Pisa, Italy.
32Univ Barcelona, IEEC UB, ICCUB, E-08028 Barcelona, Spain.
33Armenian Consortium ICRANet Armenia NAS RA, A Alikhanyan Natl Lab, Yerevan, Armenia.
34Ctr Invest Energet Medioambientales & Tecnol, E-28040 Madrid, Spain.
35Univ Innsbruck, Innsbruck, Austria.
36Port Informacio Cient PIC, E-08193 Bellaterra, Barcelona, Spain.
37Univ Wurzburg, D-97074 Wurzburg, Germany.
38Univ Turku, Finnish MAGIC Consortium, Finnish Ctr Astron ESO FINCA, FI-20014 Turku, Finland.
39Univ Oulu, Astron Res Unit, FI-90014 Oulu, 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, BG-1784 Sofia, Bulgaria.
44INAF Trieste, Trieste, Italy.
45Univ Bologna, Dept Phys & Astron, Bologna, Italy.
46Princeton Univ, Princeton, NJ 08544 USA.
47US Naval Res Lab, Washington, DC 20375 USA.
48INAFIst Radioastron, Via P Gobetti 101, I-40129 Bologna, Italy.
49Ctr Astrophys Harvard & Smithsonian, 60 Garden St, Cambridge, MA 02138 USA.
50Harvard Univ, Black Hole Initiat, 20 Garden St, Cambridge, MA 02138 USA.
51Stanford Univ, Kavli Inst Particle Astrophys & Cosmol, Dept Phys, WW Hansen Expt Phys Lab, Stanford, CA 94305 USA.
52Stanford Univ, SLAC Natl Accelerator Lab, Stanford, CA 94305 USA.
53Columbia Astrophys Lab, 550 W 120th St, New York, NY 10027 USA.
54Agenzia Spaziale Italiana ASI, Unita Ric Sci, Via Politecn, I-00133 Rome, Italy.
55ASI Sci Data Ctr, Via Politecn Snc, I-00133 Rome, Italy.
56INAF Osservatorio Astron Roma, Via Frascati 33, I-00040 Monte Porzio Catone, Italy.
57INAF Osservatorio Astrofis Torino, I-10025 Pino Torinese, TO, Italy.
58Inst Astrofis Andalucia, CSIC, Apartado 3004, E-18080 Granada, Spain.
59Bulgarian Acad Sci, Inst Astron & Natl Astron Observ, 72 Tsarigradsko Shosse Blvd, Sofia 1784, Bulgaria.
60Tuorla Observ, Dept Phys & Astron, Vaisalantie 20, FI-21500 Piikkio, Finland.
61St Petersburg State Univ, Astron Inst, Univ Skij Pr 28, St Petersburg 198504, Russia.
62Univ Crete, Dept Phys, Iraklion 71003, Greece.
63Univ Crete, Inst Plasma Phys, Iraklion 71003, Greece.
64Fdn Res & Technol Hellas, IESL, Iraklion 71110, Greece.
65Abastumani Observ, GE-0301 Mt Kanobili, Abastumani, Georgia.
66Natl Cent Univ, Grad Inst Astron, 300 Zhongda Rd, Zhongli 32001, Taiwan.
67Astron Observ, Volgina 7, Belgrade 11060, Serbia.
68Dublin Inst Adv Studies, Sch Cosm Phys, Dublin, Ireland.
69Boston Univ, Inst Astrophys Res, 725 Commonwealth Ave, Boston, MA 02215 USA.
70Kazan Fed Univ, Engelhardt Astron Observ, Tatarstan, Russia.
71Guangzhou Univ, Ctr Astrophys, Guangzhou 510006, Peoples R China.
72Pulkovo Observ, St Petersburg, Russia.
73Univ Arizona, Steward Observ, 933 N Cherry Ave, Tucson, AZ 85721 USA.
74Salt Lake Community Coll, Dept Phys, Salt Lake City, UT 84070 USA.
75Istanbul Univ, Sci Fac, Dept Astron & Space Sci, TR-34119 Istanbul, Turkey.
76Brigham Young Univ, Dept Phys & Astron, Provo, UT 84602 USA.
77Univ Colorado, Dept Phys, Denver, CO 80217 USA.
78Univ Turku, Finnish Ctr Astron ESO FINCA, FI-20014 Turku, Finland.
79Aalto Univ, Metsahovi Radio Observ, Metsahovintie 114, FI-02540 Kylmala, Finland.
80Purdue Univ, Dept Phys & Astron, W Lafayette, IN 47907 USA.
81Univ Chile, Dept Astron, Camino Observ 1515, Santiago, Chile.
82CALTECH, Owens Valley Radio Observ, Pasadena, CA 91125 USA.
83Aalto Univ, Dept Radio Sci & Engn, POB 13000, FI-00076 Aalto, Finland.
|Persistent link:|| http://urn.fi/urn:nbn:fi-fe2020120499492
|Publish Date:|| 2021-06-10
We report on a multiband variability and correlation study of the TeV blazar Mrk 421 during an exceptional flaring activity observed from 2013 April 11 to 19. The study uses, among others, data from GLAST-AGILE Support Program (GASP) of the Whole Earth Blazar Telescope (WEBT), Swift, Nuclear Spectroscopic Telescope Array (NuSTAR), Fermi Large Area Telescope, Very Energetic Radiation Imaging Telescope Array System (VERITAS), and Major Atmospheric Gamma Imaging Cherenkov (MAGIC). The large blazar activity and the 43 hr of simultaneous NuSTAR and MAGIC/VERITAS observations permitted variability studies on 15 minute time bins over three X-ray bands (3–7 keV, 7–30 keV, and 30–80 keV) and three very-high-energy (VHE; >0.1 TeV) gamma-ray bands (0.2–0.4 TeV, 0.4–0.8 TeV, and >0.8 TeV). We detected substantial flux variations on multi-hour and sub-hour timescales in all of the X-ray and VHE gamma-ray bands. The characteristics of the sub-hour flux variations are essentially energy independent, while the multi-hour flux variations can have a strong dependence on the energy of the X-rays and the VHE gamma-rays. The three VHE bands and the three X-ray bands are positively correlated with no time lag, but the strength and characteristics of the correlation change substantially over time and across energy bands. Our findings favor multi-zone scenarios for explaining the achromatic/chromatic variability of the fast/slow components of the light curves, as well as the changes in the flux–flux correlation on day-long timescales. We interpret these results within a magnetic reconnection scenario, where the multi-hour flux variations are dominated by the combined emission from various plasmoids of different sizes and velocities, while the sub-hour flux variations are dominated by the emission from a single small plasmoid moving across the magnetic reconnection layer.
Astrophysical journal. Supplement series
|Type of Publication:||
A1 Journal article – refereed
|Field of Science:||
115 Astronomy and space science
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, and FPA201790566REDC), the Indian Department of Atomic Energy, the Japanese JSPS and MEXT, the Bulgarian Ministry of Education and Science, National RI Roadmap Project DO1-153/28.08.2018 and the Academy of Finland grant No. 320045 is gratefully acknowledged. This work was also supported by the Spanish Centro de Excelencia "Severo Ochoa" SEV-2016-0588 and SEV-2015-0548, and Unidad de Excelencia "María de Maeztu" MDM-2014-0369, 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 made use of data from the NuSTAR mission, a project led by the California Institute of Technology, managed by the Jet Propulsion Laboratory, and funded by the National Aeronautics and Space Administration. We thank the NuSTAR Operations, Software, and Calibration teams for support with the execution and analysis of these observations. This research has made use of the NuSTAR Data Analysis Software (NuSTARDAS) jointly developed by the ASI Science Data Center (ASDC; Italy) and the California Institute of Technology (USA).
This research has made use of the XRT Data Analysis Software (XRTDAS) developed under the responsibility of the ASI Science Data Center (ASDC), Italy.
D.P. and A.B. are grateful to Amy Furniss and Wystan Benbow for providing the VERITAS VHE gamma-ray fluxes and for useful discussions about them. M.P. acknowledges support from the Lyman Jr. Spitzer Postdoctoral Fellowship and NASA Fermi grant No. 80NSSC18K1745., and J.F. is partially supported by NASA under contract S-15633Y. M.B. acknowledges support from NASA Headquarters under the NASA Earth and Space Science Fellowship Program (grant NNX14AQ07H) and the black hole Initiative at Harvard University, which is funded in part by the Gordon and Betty Moore Foundation (grant GBMF8273) and in part by the John Templeton Foundation.
This research was partially supported by the Bulgarian National Science Fund of the Ministry of Education and Science under grants DN 18-13/2017, DN 18-10/2017, KP-06-H28/3 (2018), and KP-06-PN38/1 (2019), as well as for the Spanish MIMECO (AYA2016-80889-P, RYC-2013-14511) and the IAA-CSIC "Severo Ochoa" program SEV-2017-0709. The St. Petersburg University team acknowledges support from Russian Science Foundation grant 17-12-01029. The Abastumani team acknowledges financial support of the project FR/638/6-320/12 by the Shota Rustaveli National Science Foundation under contract 31/77. T.G. acknowledges support from Istanbul University (Project numbers 49429 and 48285), Bilim Akademisi (BAGEP program), and TUBITAK (project numbers 13AT100-431, 13AT100-466, and 13AT60-430). The Boston University effort was supported in part by NASA grants NNX12AO90G and NNX14AQ58G. Data from the Steward Observatory spectropolarimetric monitoring project were used in this paper. This program is supported by Fermi Guest Investigator grants NNX08AW56G, NNX09AU10G, NNX12AO93G, and NNX15AU81G. The OVRO 40 m monitoring program is supported in part by NASA grants NNX08AW31G and NNX11A043G and NSF grants AST-0808050 and AST-1109911. The Metsähovi team acknowledges the support from the Academy of Finland to our observing projects (numbers 212656, 210338, 121148, and others). W.M. acknowledges support from CONICYT project Basal AFB-170002.
© 2020. The American Astronomical Society. The final authenticated version is available online at https://doi.org/10.3847/1538-4365/ab89b5.