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A fast, very-high-energy γ-ray flare from BL Lacertae during a period of multi-wavelength activity in June 2015 |
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| Author: | Acciari, V. A.1,2; Ansoldi, S.3,4,5,6,7; Antonelli, L. A.8; |
| Organizations: |
1Inst Astrofis Canarias, Tenerife 38206, Spain. 2Univ La Laguna, Dept Astrofis, E-38206 Tenerife, Spain. 3Univ Udine, I-33100 Udine, Italy.
4INFN Trieste, I-33100 Udine, Italy.
5Univ Tokyo, ICRR, Chiba 2778582, Japan. 6Kyoto Univ, Dept Phys, Kyoto 6068502, Japan. 7Tokai Univ, Kanagawa, Saitama 2591292, Japan. 8Natl Inst Astrophys INAF, I-00136 Rome, Italy. 9Swiss Fed Inst Technol, CH-8093 Zurich, Switzerland. 10Tech Univ Dortmund, D-44221 Dortmund, Germany. 11Univ Rijeka, Rijeka 51000, Croatia. 12Univ Split, FESB, Split 21000, Croatia. 13Univ Zagreb, FER, Zagreb 10000, Croatia. 14Univ Osijek, Osijek 31000, Croatia. 15Rudjer Boskovic Inst, Zagreb 10000, Croatia. 16HBNI, Saha Inst Nucl Phys, 1-AF Bidhannagar,Sect 1, Kolkata 700064, India. 17Max Planck Inst Phys & Astrophys, D-80805 Munich, Germany. 18URCA, CBPF, BR-22290180 Rio De Janeiro, RJ, Brazil. 19Univ Complutense, Unidad Particulas & Cosmol UPARCOS, E-28040 Madrid, Spain. 20Univ Lodz, Dept Astrophys, PL-90236 Lodz, Poland. 21Deutsch Elektronen Synchrotron DESY, D-15738 Zeuthen, Germany. 22Univ Padua, I-35131 Padua, Italy. 23INFN, I-35131 Padua, Italy. 24Humboldt Univ, Inst Phys, D-12489 Berlin, Germany. 25Univ Trieste, Dipartimento Fis, I-34127 Trieste, Italy. 26BIST, IFAE, Bellaterra 08193, Barcelona, Spain. 27Univ Siena, I-53100 Siena, Italy. 28INFN Pisa, I-53100 Siena, Italy. 29Univ Pisa, I-56126 Pisa, Italy. 30INFN Pisa, I-56126 Pisa, Italy. 31PIC, Bellaterra 08193, Barcelona, Spain. 32Univ Wurzburg, D-97074 Wurzburg, Germany. 33Univ Turku, Finnish MAG Consortium Tuorla Observ, FIN-20014 Turku, Finland. 34Univ Turku, Finnish Ctr Astron ESO FINCA, FIN-20014 Turku, Finland. 35Univ Oulu, Astron Div, Oulu 90014, Finland. 36Univ Autonoma Barcelona, Dept Fis, Bellaterra 08193, Spain. 37Univ Autonoma Barcelona, CERES IEEC, Bellaterra 08193, Spain. 38Univ Barcelona, ICCUB, IEEC UB, E-08028 Barcelona, Spain. 39Bulgarian Acad Sci, Inst Nucl Res & Nucl Energy, Sofia 1784, Bulgaria. 40INAF Trieste, Trieste, Italy. 41Univ Bologna, Dept Phys & Astron, Bologna, Italy. 42Univ Bologna, Dipartimento Fis & Astron, Via Gobetti 93-2, I-40129 Bologna, Italy. 43Inst Radioastron Bologna, INAF, Via P Gobetti 101, I-40129 Bologna, Italy. 44Natl Astron Observ Japan, Mizusawa VLBI Observ, 2-21-1 Osawa, Mitaka, Tokyo 1818588, Japan. 45Grad Univ Adv Studies SOKENDAI, Dept Astron Sci, 2-21-1 Osawa, Mitaka, Tokyo 2211, Japan. 46Boston Univ, Inst Astrophys Res, 725 Commonwealth Ave, Boston, MA 02215 USA. 47St Petersburg State Univ, Astron Inst, Univ skij Pr 28, St Petersburg 198504, Russia. 48Univ Turku, Tuorla Observ, Dept Phys & Astron, Turku, Finland. 49Pulkovo Observ, St Petersburg, Russia. 50Crimean Astrophys Observ, Crimea, Russia. 51Aalto Univ, Metsahovi Radio Observ, Metsahovintie 114, Kylml 02540, Finland. 52Aalto Univ, Dept Elect & Nanoengn, POB 15500, Aalto 00076, Finland. 53Tartu Observ, Observatooriumi 1, EE-61602 Toravere, Estonia. 54CSIC, Inst Astrofis Andalucia, Apdo 3004, Granada 18080, Spain. |
| Format: | article |
| Version: | published version |
| Access: | open |
| Online Access: | PDF Full Text (PDF, 0.9 MB) |
| Persistent link: | http://urn.fi/urn:nbn:fi-fe202003097656 |
| Language: | English |
| Published: |
EDP Sciences,
2019
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| Publish Date: | 2020-03-09 |
| Description: |
AbstractThe mechanisms producing fast variability of the γ-ray emission in active galactic nuclei (AGNs) are under debate. The MAGIC telescopes detected a fast, very-high-energy (VHE, E > 100 GeV) γ-ray flare from BL Lacertae on 2015 June 15. The flare had a maximum flux of (1.5 ± 0.3) × 10−10 photons cm−2 s−1 and halving time of 26 ± 8 min. The MAGIC observations were triggered by a high state in the optical and high-energy (HE, E > 100 MeV) γ-ray bands. In this paper we present the MAGIC VHE γ-ray data together with multi-wavelength data from radio, optical, X-rays, and HE γ rays from 2015 May 1 to July 31. Well-sampled multi-wavelength data allow us to study the variability in detail and compare it to the other epochs when fast, VHE γ-ray flares have been detected from this source. Interestingly, we find that the behaviour in radio, optical, X-rays, and HE γ-rays is very similar to two other observed VHE γ-ray flares. In particular, also during this flare there was an indication of rotation of the optical polarization angle and of activity at the 43 GHz core. These repeating patterns indicate a connection between the three events. We also test modelling of the spectral energy distribution based on constraints from the light curves and VLBA observations, with two different geometrical setups of two-zone inverse Compton models. In addition we model the γ-ray data with the star-jet interaction model. We find that all of the tested emission models are compatible with the fast VHE γ-ray flare, but all have some tension with the multi-wavelength observations. see all
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| Series: |
Astronomy and astrophysics |
| ISSN: | 0004-6361 |
| ISSN-E: | 1432-0746 |
| ISSN-L: | 0004-6361 |
| Volume: | 623 |
| Article number: | A175 |
| DOI: | 10.1051/0004-6361/201834010 |
| OADOI: | https://oadoi.org/10.1051/0004-6361/201834010 |
| Type of Publication: |
A1 Journal article – refereed |
| Field of Science: |
115 Astronomy and space science |
| Subjects: | |
| Funding: |
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 (FPA2015-69818-P, FPA2012-36668, FPA2015-68378-P, FPA2015-69210-C6-2-R, FPA2015-69210-C6-4-R, FPA2015-69210-C6-6-R, AYA2015-71042-P, AYA2016-76012-C3-1-P, ESP2015-71662-C2-2-P, FPA201790566REDC), the Indian Department of Atomic Energy and the Japanese JSPS and MEXT is gratefully acknowledged. This work was also supported by the Spanish Centro de Excelencia “Severo Ochoa” SEV-2016-0588and SEV-2015-0548, and Unidad de Excelencia “María de Maeztu” MDM-2014-0369, by the Croatian Science Foundation (HrZZ) Project IP-2016-06-9782and the University of Rijeka Project 13.12.1.3.02, 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, CNPqand FAPERJ. The work of the author M. Vazquez Acosta is financed with grant RYC-2013-14660 of MINECO. F. D’Ammando is grateful for support from the National Research Council of Science and Technology, Korea (EU-16-001). 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 dePhysique Nucléaire et de Physique des Particules in France, the Agenzia SpazialeItaliana 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 DOEContract DE-AC02-76SF00515. 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. Acquisition and reduction of the MAPCAT data was supported in part by MINECO through grants AYA2010-14844, AYA2013-40825-P, and AYA2016-80889-P, and by the Regional Government of Andalucía through grant P09-FQM-4784. The MAPCAT observations were carried out at the German-Spanish Calar Alto Observatory, which is jointly operated by the Max-Plank-Institut für Astronomie and the Instituto de Astrofísica de Andalucía-CSIC. The St. Petersburg University team acknowledges support from Russian Science Foundation grant 17-12-01029.This publication makes use of data obtained at the Metsähovi Radio Observatory, operated by Aalto University, Finland. This study makes use of 43-GHzVLBA data from the VLBA-BU Blazar Monitoring Program (VLBA-BU-BLAZAR; http://www.bu.edu/blazars/VLBAproject.html), funded by NASA through the Fermi Guest Investigator Program. The VLBA is an instrument of the National Radio Astronomy Observatory. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated by Associated Universities, Inc. The BU group acknowledges support from NASA Fermi GI program grant 80NSSC17K0694 and US National Science Foundation grant AST-1615796. The OVRO 40-m monitoring program is supported in part by NASA grants NNX08AW31G, NNX11A043G and NNX14AQ89G, and NSF grants AST-0808050 and AST-1109911. |
| Copyright information: |
© ESO 2019. |