A1 Vertaisarvioitu alkuperäisartikkeli tieteellisessä lehdessä
Multi-year characterisation of the broad-band emission from the intermittent extreme BL Lac 1ES 2344+514
Tekijät: Abe H, Abe S, Acciari V, Agudo I, Aniello T, Ansoldi S, Antonelli L, Arbet Engels A, Arcaro C, Artero M, Asano K, Baack D, Babić A, Baquero A, Barres De Almeida U, Batković I, Baxter J, Becerra González J, Bernardini E, Bernete J, Berti A, Besenrieder J, Bigongiari C, Biland A, Blanch O, Bonnoli G, Bošnjak Ž, Burelli I, Busetto G, Campoy-Ordaz A, Carosi A, Carosi R, Carretero-Castrillo M, Castro-Tirado A, Chai Y, Cifuentes A, Cikota S, Colombo E, Contreras J, Cortina J, Covino S, D'Amico G, D'Ammando F, D'Elia V, Da Vela P, Dazzi F, De Angelis A, De Lotto B, Del Popolo A, Delfino M, Delgado J, Delgado Mendez C, Depaoli D, Di Pierro F, Di Venere L, Dominis Prester D, Dorner D, Doro M, Elsaesser D, Emery G, Escudero J, Fariña L, Fattorini A, Foffano L, Font L, Fukami S, Fukazawa Y, García López R, Gasparyan S, Gaug M, Giesbrecht Paiva J, Giglietto N, Giordano F, Gliwny P, Grau R, Green J, Hadasch D, Hahn A, Heckmann L, Herrera J, Hrupec D, Hütten M, Imazawa R, Inada T, Iotov R, Ishio K, Jiménez Martínez I, Jormanainen J, Kerszberg D, Kluge G, Kobayashi Y, Kouch P, Kubo H, Kushida J, Láinez Lezáun M, Lamastra A, Leone F, Lindfors E, Linhoff L, Lombardi S, Longo F, López-Moya M, López-Oramas A, Loporchio S, Lorini A, MacHado De Oliveira Fraga B, Majumdar P, Makariev M, Maneva G, Mang N, Manganaro M, Mariotti M, Martínez M, Martínez-Chicharro M, Mas-Aguilar A, Mazin D, Menchiari S, Mender S, Miceli D, Miener T, Miranda J, Mirzoyan R, Molero González M, Molina E, Mondal H, Moralejo A, Morcuende D, Nakamori T, Nanci C, Neustroev V, Nigro C, Nikolić L, Nishijima K, Njoh Ekoume T, Noda K, Nozaki S, Ohtani Y, Okumura A, Otero-Santos J, Paiano S, Palatiello M, Paneque D, Paoletti R, Paredes J, Pavlović D, Persic M, Pihet M, Pirola G, Podobnik F, Prada Moroni P, Prandini E, Principe G, Priyadarshi C, Rhode W, Ribó M, Rico J, Righi C, Sahakyan N, Saito T, Satalecka K, Saturni F, Schleicher B, Schmidt K, Schmuckermaier F, Schubert J, Schweizer T, Sciaccaluga A, Sitarek J, Spolon A, Stamerra A, Strišković J, Strom D, Suda Y, Tajima H, Takeishi R, Tavecchio F, Temnikov P, Terauchi K, Terzić T, Teshima M, Tosti L, Truzzi S, Tutone A, Ubach S, Van Scherpenberg J, Ventura S, Verguilov V, Viale I, Vigorito C, Vitale V, Walter R, Wunderlich C, Yamamoto T, Perri M, Verrecchia F, Leto C, Das S, Chatterjee R, Raiteri C, Villata M, Semkov E, Ibryamov S, Bachev R, Strigachev A, Damljanovic G, Vince O, Jovanovic M, Stojanovic M, Larionov V, Grishina T, Kopatskaya E, Larionova E, Morozova D, Savchenko S, Troitskiy I, Troitskaya Y, Vasilyev A, Chen W, Hou W, Lin C, Tsai A, Jorstad S, Weaver Z, Acosta-Pulido J, Carnerero M, Carosati D, Kurtanidze S, Kurtanidze O, Jordan B, Ivanidze R, Gazeas K, Vrontaki K, Hovatta T, Liodakis I, Readhead A, Kiehlmann S, Zheng W, Filippenko A, Fallah Ramazani V
Kustantaja: EDP Sciences
Julkaisuvuosi: 2024
Journal: Astronomy and Astrophysics
Tietokannassa oleva lehden nimi: Astronomy and Astrophysics
Artikkelin numero: A114
Vuosikerta: 682
eISSN: 1432-0746
DOI: https://doi.org/10.1051/0004-6361/202347845
Verkko-osoite: https://www.aanda.org/articles/aa/full_html/2024/02/aa47845-23/aa47845-23.html
Rinnakkaistallenteen osoite: https://research.utu.fi/converis/portal/detail/Publication/387309370
Preprintin osoite: https://arxiv.org/abs/2310.03922
Aims.
The BL Lac 1ES 2344+514 is known for temporary extreme properties characterised by a shift of the synchrotron spectral energy distribution (SED) peak energy νsynch,p above 1 keV. While those extreme states have only been observed during high flux levels thus far, additional multi-year observing campaigns are required to achieve a coherent picture. Here, we report the longest investigation of the source from radio to very high energy (VHE) performed so far, focussing on a systematic characterisation of the intermittent extreme states.
Methods.
We organised a monitoring campaign covering a 3-year period from 2019 to 2021. More than ten instruments participated in the observations in order to cover the emission from radio to VHE. In particular, sensitive X-ray measurements by XMM-Newton, NuSTAR, and AstroSat took place simultaneously with multi-hour MAGIC observations, providing an unprecedented constraint of the two SED components for this blazar.
Results.
While our results confirm that 1ES 2344+514 typically exhibits νsynch,p > 1 keV during elevated flux periods, we also find periods where the extreme state coincides with low flux activity. A strong spectral variability thus happens in the quiescent state, and is likely caused by an increase in the electron acceleration efficiency without a change in the electron injection luminosity. On the other hand, we also report a strong X-ray flare (among the brightest for 1ES 2344+514) without a significant shift of νsynch,p. During this particular flare, the X-ray spectrum is among the softest of the campaign. It unveils complexity in the spectral evolution, where the common harder-when-brighter trend observed in BL Lacs is violated. By combining Swift-XRT and Swift-UVOT measurements during a low and hard X-ray state, we find an excess of the UV flux with respect to an extrapolation of the X-ray spectrum to lower energies. This UV excess implies that at least two regions significantly contribute to the infrared/optical/ultraviolet/X-ray emission. Using the simultaneous MAGIC, XMM-Newton, NuSTAR, and AstroSat observations, we argue that a region possibly associated with the 10 GHz radio core may explain such an excess. Finally, we investigate a VHE flare, showing an absence of simultaneous variability in the 0.3-2 keV band. Using time-dependent leptonic modelling, we show that this behaviour, in contradiction to single-zone scenarios, can instead be explained by a two-component model. © The Authors 2024.
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