A4 Vertaisarvioitu artikkeli konferenssijulkaisussa
Long-term study of the intermittent extreme behaviour of 1ES 2344+514
Tekijät: A. Arbet-Engels; H. A. Mondal; S. Fukami; F. D’Ammando; D. Dorner; R. Chatterjee; P. Majumdar; M. Manganaro; T. Hovatta; M. Villata; M. Perri; F. Verrechia; C. Leto; A. Filippenko; W. Zheng and MAGIC Collaboration
Konferenssin vakiintunut nimi: International Cosmic Ray Conference
Kustantaja: Sissa Medialab Srl
Julkaisuvuosi: 2024
Journal: POS Proceedings of Science
Tietokannassa oleva lehden nimi: Proceedings of Science
Artikkelin numero: 788
Vuosikerta: 444
eISSN: 1824-8039
DOI: https://doi.org/10.22323/1.444.0788
Verkko-osoite: https://pos.sissa.it/444/788/
Rinnakkaistallenteen osoite: https://research.utu.fi/converis/portal/detail/Publication/478210141
Extreme high-frequency-peaked BL Lac objects (EHBLs) are the most energetic persistent sources in the Universe. They are characterized by a spectral energy distribution (SED) featuring a synchrotron peak energy above 1 keV. 1ES 2344+514 is a blazar known to behave as an EHBL intermittently. Until now, its EHBL nature was only reported during flares, but a coherent picture is missing as unbiased monitoring campaigns are lacking. This work presents the longest observing campaign from radio to very-high-energy (VHE) frequencies performed so far on 1ES2344+514. Using observations during 2019-2021, we carry out a systematic investigation of the intermittent EHBL phases. Together with MAGIC, the dataset also includes X-ray observations from NuSTAR, XMM-Newton, and AstroSAT, providing an unprecedented determination of the two SED components. For the first time we report a clear EHBL behaviour during a low flux activity in 1ES 2344+514. It implies a significant hardening of the electron distribution inside the jet independent of flux. We also detect a bright X-ray state characterized by an unusually soft spectra, thus violating the harder-when-brighter relation typically found in blazars. The SED study further reveals an excess in the ultraviolet data with respect to the extrapolation of the X-ray spectrum, suggesting at least two regions contributing to the synchrotron flux. Finally we investigate a gamma-ray flare not accompanied by an X-ray counterpart. This peculiar outburst is interpreted using a time-dependent model involving two emitting components.
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Julkaisussa olevat rahoitustiedot:
The financial support of the German BMBF, MPG, and HGF; the Italian INFN and INAF; the Swiss National Fund SNF; the grants PID2019-104114RB-C31, PID2019-104114RB-C32, PID2019-104114RB-C33, PID2019-105510GBC31, PID2019-107847RB-C41, PID2019-107847RB-C42, PID2019-107847RB-C44, and PID2019-107988GB-C22 funded by the Spanish MCIN/AEI/10.13039/501100011033; 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 DO1-400/18.12.2020; and the Academy of Finland grant No. 320045 is gratefully acknowledged.
This work was also supported by the Centros de Excelencia "Severo Ochoa" and Unidades "María de Maeztu" program of the Spanish MCIN/AEI/10.13039/501100011033 (SEV-2016-0588, CEX2019-000920-S, CEX2019-000918-M, CEX2021-001131-S, MDM-2015-0509-18-2) and by the CERCA institution of the Generalitat de Catalunya; by the Croatian Science Foundation (HrZZ) Project IP-2016-06-9782 and the University of Rijeka Project uniri-prirod-18-48; by the Deutsche Forschungsgemeinschaft (SFB1491 and SFB876); the Polish Ministry of Education and Science grant No. 2021/WK/08; and by the Brazilian MCTIC, CNPq, and FAPERJ.
A.A.E and D.P acknowledge support from the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany’s Excellence Strategy – EXC-2094 – 390783311. 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 also made use of the XRT Data Analysis Software (XRTDAS) developed under the responsibility of the ASI Science Data Center (ASDC), Italy.
The Abastumani team acknowledges financial support by the Shota Rustaveli NSF of Georgia under contract FR-19-6174. The R-band photometric data from the University of Athens Observatory (UOAO) were obtained using robotic and remotely controlled instruments at the facilities. The research at Boston University was supported in part by NASA Fermi GI grant 80NSSC22K1571 and U.S. National Science Foundation grant AST-2108622. This study was based, in part, on observations conducted using the 1.8 m Perkins Telescope Observatory (PTO) in Arizona (USA), which is owned and operated by Boston University.
This research was partially supported by the Bulgarian National Science Fund of the Ministry of Education and Science under grants KP-06-H38/4 (2019), KP-06-KITAJ/2 (2020), and KP-06-H68/4 (2022). The Skinakas Observatory is a collaborative project of the University of Crete, the Foundation for Research and Technology – Hellas, and the Max-Planck-Institut für Extraterrestrische Physik. GD, OV, MDJ, and MS acknowledge support by the Astronomical Station Vidojevica, funding from the Ministry of Science, Technological Development, and Innovation of the Republic of Serbia (contract No. 451-03-47/2023-01/200002), by the EC through project BELISSIMA (call FP7-REGPOT-2010-5, No. 265772), observing and financial grant support from the Institute of Astronomy and Rozhen NAO BAS through the bilateral SANU-BAN joint research project GAIA ASTROMETRY AND FAST VARIABLE ASTRONOMICAL OBJECTS, and support by the SANU project F-187.
This paper used observations made with the IAC-80 telescope operated on the island of Tenerife by the Instituto de Astrofísica de Canarias in the Spanish Observatorio del Teide and also observations made with the LCOGT 0.4 m telescope network, one of whose nodes is located in the Spanish Observatorio del Teide. This research has made use of data from the OVRO 40-m monitoring program, supported by private funding from the California Institute of Technology and the Max Planck Institute for Radio Astronomy, and by NASA grants NNX08AW31G, NNX11A043G, and NNX14AQ89G, and NSF grants AST-0808050 and AST-1109911. S.K. acknowledges support from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program under grant agreement No. 771282.
