An intermittent extreme BL Lac: MWL study of 1ES 2344+514 in an enhanced state

Acciari V. A.; Ansoldi S.; Antonelli L. A.; Arbet Engels A.; Babic A.; Banerjee B.; Barres de Almeida U.; Barrio J. A.; Becerra Gonzalez J.; Bednarek W.; Bellizzi L.; Bernardini E.; Berti A.; Besenrieder J.; Bhattacharyya W.; Bigongiari C.; Blanch O.; Bonnoli G.; Bosnjak Z.; Busetto G.; Carosi R.; Ceribella G.; Cerruti M.; Chai Y.; Chilingaryan A.; Cikota S.; Colak S. M.; Colin U.; Colombo E.; Contrera J. L.; Cortina J.; Covino S.; D'Elia V.; Da Vela P.; Dazzi F.; De Angelis A.; De Lotto B.; Delfino M.; Delgado J.; Depaoli D.; Di Pierro F.; Di Venere L.; Do Souto Espineira E.; Dominis Prester D.; Donini A.; Doro M.; Elsaesser D.; Fallah Ramazani V.; Fattorini A.; Ferrara G.; Foffano L.; Fonsec M. V.; Font L.; Fruck C.; Fukami S.; Garcia López R. J.; Garczarczyk M.; Gasparyan S.; Gaug M.; Giglietto N.; Giordano F.; Godinovic N.; Gliwny P.; Green D.; Hadasch D.; Hahn A.; Herrera J.; Hoang J.; Hrupec D.; Hütten M.; Inada T.; Inoue S.; Ishio K.; Iwamura Y.; Jouvin L.; Kajiwara Y.; Kerszberg D.; Kobayashi Y.; Kubo H.; Kushida J.; Lamastra A.; Lelas D.; Leone F.; Lindfors E.; Lombardi S.; Longo F.; López M.; López-Coto R.; López-Oramas A.; Loporchio S.; Machado de Oliveira Fraga B.; Maggio C.; Majumdar P.; Makariev M.; Mallamaci M.; Maneva G.; Manganaro M.; Maraschi L.; Mariotti M.; Martinez M.; Mazin D.; Mender S.; Mićanovic S.; Miceli D.; Miener T.; Minev M.; Miranda J. M.; Mirzoyan R.; Molina E.; Moralejo A.; Morcuende D.; Moreno V.; Moretti E.; Munar-Adrover P.; Neustroev V.; Nigro C.; Nilsson K.; Ninci D.; Nishijima K.; Noda K.; Nogues L.; Nozaki S.; Ohtani Y.; Oka T.; Otero-Santos J.; Paiano S.; Palatiello M.; Paneque D.; Paoletti R.; Parede J. M.; Pavletic L.; Penil P.; Peresano M.; Persic M.; Prada Moroni P. G.; Prandini E.; Puljak I.; Ribo M.; Rico J.; Righi C.; Rugliancich A.; Saha L.; Sahakyan N.; Saito T.; Sakurai S.; Satalecka K.; Schleicher B.; Schmidt K.; Schweizer T.; Sitarek J.; Snidaric I.; Sobczynska D.; Spolon A.; Stamerra A.; Strom D.; Strzys M.; Suda Y.; Suric T.; Takahashi M.; Tavecchio F.; Temnikov P.; Terzić T.; Teshima M.; Torres-Alba N.; Tosti L.; Van Scherpenberg J.; Vanzo G.; Vazquez Acosta M.; Ventura S.; Verguilov V.; Vigorito C. F.; Vitale V.; Vovk I.; Will M.; Zarić D.; Baack D.; Balbo M.; Beck M.; Biederbeck N.; Biland A.; Blank M.; Bretz T.; Bruegge K.; Bulinski M.; Buss J.; Doerr M.; Dorner D.; Hildebrand D.; Iotov R.; Klinger M.; Mannheim K.; Achim Mueller S.; Neise D.; Neronov A.; Nöthe M.; Paravac A.; Rhode W.; Schleicher B.; Sedlaczek K.; Shukla A.; Sliusar V.; Tani L.; Theissen F.; Walter R.; Acosta Pulido J.; Filippenko A. V.; Hovatta T.; Kiehlmann S.; Larionov V. M.; Max-Moerbeck W.; Raiteri C. M.; Readhead A. C. S.; Segon M.; Villata M.; Zheng W.

An intermittent extreme BL Lac: MWL study of 1ES 2344+514 in an enhanced state

Acciari V. A.

•

Ansoldi S.

•

Antonelli L. A.

altro

Zheng W.

2020

journal article

Periodico

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY

Abstract

Extreme high-frequency BL Lacs (EHBL) feature their synchrotron peak of the broad-band spectral energy distribution (SED) at vs ≥ 1017 Hz. The BL Lac object 1ES 2344+514 was included in the EHBL family because of its impressive shift of the synchrotron peak in 1996. During the following years, the source appeared to be in a low state without showing any extreme behaviours. In 2016 August, 1ES 2344+514 was detected with the groundbased γ -ray telescope FACT during a high γ -ray state, triggering multiwavelength (MWL) observations. We studied the MWL light curves of 1ES 2344+514 during the 2016 flaring state, using data from radio to very-high-energy (VHE) γ -rays taken with OVRO, KAIT, KVA, NOT, some telescopes of the GASP-WEBT collaboration at the Teide, Crimean, and St. Petersburg observatories, Swift-UVOT, Swift-XRT, Fermi-LAT, FACT, and MAGIC. With simultaneous observations of the flare, we built the broad-band SED and studied it in the framework of a leptonic and a hadronic model. The VHE γ -ray observations show a flux level of 55 per cent of the Crab Nebula flux above 300 GeV, similar to the historical maximum of 1995. The combination of MAGIC and Fermi-LAT spectra provides an unprecedented characterization of the inverse-Compton peak for this object during a flaring episode. The _ index of the intrinsic spectrum in the VHE γ -ray band is 2.04 ± 0.12stat ± 0.15sys.We find the source in an extreme state with a shift of the position of the synchrotron peak to frequencies above or equal to 1018 Hz.