Suchergebnisse

L'intégration effective de la restauration écologique dans la gestion des espaces naturels nécessite la définition de zones et d'actions prioritaires. À grande échelle spatiale, les priorités sont généralement définies par les experts en termes de facteurs écologiques, en particulier en fonction de la distribution d'espèces ou de quelques services écosystémiques. Cependant, les décisions de gestion doivent faire face à différents habitats naturels et répondre aux multiples exigences et aspirations de la société. L'émergence de nouveaux outils pour mieux identifier et analyser les critères de priorité et déterminer les meilleures alternatives de gestion, en intégrant les perspectives écologiques et socio-économiques sont nécessaires. Nous avons développé une approche participative pour identifier les sites prioritaires de restauration dans une région de 224 472 ha dans la Démarcation de la forêt de Crevillent, dans le sud-est semi-aride de l'Espagne. Le défi était de développer une méthodologie rigoureuse mais accessible qui pourrait être extrapolée à d'autres régions. Une plate-forme de 88 parties prenantes a été invitée à identifier et à pondérer les critères prioritaires pour la restauration. Les parties prenantes ont identifié cinq groupes de critères correspondant aux environnements naturels et semi-naturels, aux environnements hautement anthropisés, aux fonctions de l'écosystème, aux processus à l'échelle du paysage et aux aspects socio-économiques et culturels. Le poids intégré des critères étudiés a montré que ceux liés aux environnements hautement anthropisés (décharges, bords des rivières, carrières abandonnées, cultures pluviales et cultures irriguées) et aux fonctions de l'écosystème (facteurs clés pour réduire le risque et la vulnérabilité aux feux de forêt, l'érosion, la pollution de l'eau) ont reçu la plus haute priorité, ainsi que pour les zones à forte valeur culturelle et ethnologique. En revanche, la priorité pour les environnements naturels et semi-naturels et les caractéristiques à l'échelle du paysage était plus faible. Nous discutons de ces résultats et de la possibilité d'utiliser ce protocole pour soutenir la prise de décision concernant les actions de restauration écologique dans ce paysage méditerranéen.

The effective integration of ecological restoration (ER) into land management requires the definition of priority areas and actions. At large spatial scales, priorities are commonly defined by experts in terms of ecological factors, particularly species distribution or a small set of ecosystem services. However, management decisions must deal with different habitats, and respond to society multiple demands and aspirations. New tools for identifying and analyzing priority criteria and determining best management alternatives, integrating ecological and socio-economic perspectives are needed. We developed a participatory approach to identify priority areas for restoration in a 224,472 Ha area in Crevillent Forest Demarcation, southeast semi-arid Spain. The challenge was to develop a rigorous yet accessible methodology that could be extrapolated to other regions. An 88-stakeholder platform was asked to identify and weight priority criteria for ER. Stakeholders identified five groups of criteria corresponding to natural and semi-natural environments, highly-humanized environments, criteria related to ecosystem functions, criteria related to landscape-scale processes, and socio-economic and cultural criteria. The integrated weight of the studied criteria showed that highly-humanized environments (landfills and waste dumps, river margins, unused quarries, rainfed crops, and irrigated crops) and criteria related to ecosystem function (key areas to reduce wildfire risk and vulnerability, key areas to reduce erosion, key areas to reduce water pollution) received the highest priority, together with areas with high cultural and ethnologic value. In contrast, the priority for natural and semi-natural environments and landscape-scale features was lower. We discuss these results and the feasibility of using this protocol to support decision making concerning ecological restoration actions in this Mediterranean landscape.

We present the results of a process to attempt to identify 100 questions that, if answered, would make a substantial difference to terrestrial and marine landscape restoration in Europe. Representatives from a wide range of European governmental and non-governmental conservation organisations, universities, independent ecologists and land managers compiled 677 questions relating to all aspects of European landscape restoration for nature and people. The questions were shortlisted by an email vote, followed by a two-day workshop, to produce the final list of 100 questions. Many of the final questions evolved through a process of modification and combination as the workshop progressed. The questions are divided into eight sections: conservation of biodiversity; connectivity, migration and translocations; delivering and evaluating restoration; natural processes; ecosystem services; social and cultural aspects of restoration; policy and governance; and economics. We anticipate that these questions will help identify new directions for researchers and policy-makers and assist funders and programme managers in allocating funds and planning projects, resulting in improved understanding and implementation of landscape-scale ecological restoration in Europe.

The 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. © ESO 2019. ; 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, FPA 2015-68378-P, FPA2015-69210-C6-2-R, FPA2015-69210-C6-4-R, FPA201569210-C6-6-R, AYA2015-71042-P, AYA2016-76012-C3-1-P, ESP2015-71662C2-2-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-2016-0588 and SEV-2015-0548, and Unidad de Excelencia >Maria de Maeztu> MDM-20140369, by the Croatian Science Foundation (HrZZ) Project IP-2016-06-9782 and 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, CNPq and 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 (EU16-001). 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 a l'Energie Atomique and the Centre National de la Recherche Scientifique/Institut National de Physique Nucleaire 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'Etudes Spatiales in France. This work performed in part under DOE Contract 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 AYA201014844, AYA2013-40825-P, and AYA2016-80889-P, and by the Regional Government of Andalucia 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 fur Astronomie and the Instituto de Astrofisica de Andalucia-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 Metsahovi Radio Observatory, operated by Aalto University, Finland. This study makes use of 43-GHz VLBA data from the VLBA-BU Blazar Monitoring Program (VLBA-BUBLAZAR; 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. ; Peer Reviewed

Context. The BL Lac object S5 0716+714, a highly variable blazar, underwent an impressive outburst in January 2015 (Phase A), followed by minor activity in February (Phase B). The MAGIC observations were triggered by the optical flux observed in Phase A, corresponding to the brightest ever reported state of the source in the R-band. Aims.The comprehensive dataset collected is investigated in order to shed light on the mechanism of the broadband emission. Methods. Multi-wavelength light curves have been studied together with the broadband spectral energy distributions (SEDs). The sample includes data from Effelsberg, OVRO, Metsähovi, VLBI, CARMA, IRAM, SMA, Swift-UVOT, KVA, Tuorla, Steward, RINGO3, KANATA, AZT-8+ST7, Perkins, LX-200, Swift-XRT, NuSTAR, Fermi-LAT and MAGIC. Results. The flaring state of Phase A was detected in all the energy bands, providing for the first time a multi-wavelength sample of simultaneous data from the radio band to the very-high-energy (VHE, E > 100 GeV). In the constructed SED, the Swift-XRT+NuSTAR data constrain the transition between the synchrotron and inverse Compton components very accurately, while the second peak is constrained from 0.1 GeV to 600 GeV by Fermi+MAGIC data. The broadband SED cannot be described with a one-zone synchrotron self-Compton model as it severely underestimates the optical flux in order to reproduce the X-ray to -ray data. Instead we use a two-zone model. The electric vector position angle (EVPA) shows an unprecedented fast rotation. An estimation of the redshift of the source by combined high-energy (HE, 0.1 GeV < E < 100 GeV) and VHE data provides a value of z = 0:31 ± 0:02 ± 0:05, confirming the literature value. Conclusions. The data show the VHE emission originating in the entrance and exit of a superluminal knot in and out of a recollimation shock in the inner jet. A shock-shock interaction in the jet seems responsible for the observed flares and EVPA swing. This scenario is also consistent with the SED modeling. © ESO 2018. ; We would like to thank the Instituto de Astrofisica de Canarias for the excellent working conditions at the Observatorio del Roque de los Muchachos in La Palma. 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, CSD2009-00064), and the Japanese JSPS and MEXT is gratefully acknowledged. This work was also supported by the Spanish Centro de Excelencia "Severo Ochoa" SEV-2012-0234 and SEV-2015-0548, and Unidad de Excelencia "Maria de Maeztu" MDM-2014-0369, by the Croatian Science Foundation (HrZZ) Project IP-2016-06-9782 and 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, 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 a l'Energie Atomique and the Centre National de la Recherche Scientifique/Institut National de Physique Nucleaire 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'Etudes Spatiales in France. This research was supported by an appointment to the NASA Postdoctoral Program at the Goddard Space Flight Center, administered by Universities Space Research Association through a contract with NASA. We thank the Swift team duty scientists and science planners. ; The Metsahovi team acknowledges the support from the Academy of Finland to our observing projects (numbers 212656, 210338, 121148, and others). The VLBA is an instrument of the Long Baseline Observatory. The Long Baseline Observatory is a facility of the National Science Foundation operated by Associated Universities, Inc. The Sub-millimeter Array is a joint project between the Smithsonian Astrophysical Observatory and the Academia Sinica Institute of Astronomy and Astrophysics and is funded by the Smithsonian Institution and the Academia Sinica. 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. The St. Petersburg University team acknowledges support from Russian Science Foundation grant 17-12-01029. The BU group acknowledges support by NASA under Fermi Guest Investigator grant NNX14AQ58G and by NSF under grant AST-1615796. Part of this work was done with funding by the UK Space Agency. 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 under cooperative agreement by Associated Universities, Inc. The PRISM (Perkins Re-Imaging SysteM) camera at Lowell Observatory was developed by K. Janes et al. at BU and Lowell Observatory, with funding from the NSF, BU, and Lowell Observatory. This paper makes use of data obtained with the 100m Effelsberg radio-telescope, which is operated by the Max-Planck-Institut fur Radioastronomy (MPIfR) in Bonn (Germany). Part of this work is based on archival data, software or online services provided by the ASI Science Data Center (ASDC). PYRAF is a product of the Space Telescope Science Institute, which is operated by AURA for NASA. This paper is partly based on observations carried out with the IRAM 30 m. IRAM is supported by INSU/CNRS (France), MPG (Germany) and IGN (Spain). IA acknowledges support by a Ramon y Cajal grant of the Ministerio de Economia, Industria y Competitividad (MINECO) of Spain. The research at the IAA-CSIC was supported in part by the MINECO through grants AYA2016-80889-P, AYA2013-40825-P, and AYA2010-14844, and by the regional government of Andalucia through grant P09-FQM-4784. The Liverpool Telescope is operated by JMU with financial support from the UK-STFC. ; Peer Reviewed

The Cherenkov Telescope Array (CTA) is the major next-generation observatory for ground-based very-high-energy gamma-ray astronomy. It will improve the sensitivity of current ground-based instruments by a factor of five to twenty, depending on the energy, greatly improving both their angular and energy resolutions over four decades in energy (from 20 GeV to 300 TeV). This achievement will be possible by using tens of imaging Cherenkov telescopes of three successive sizes. They will be arranged into two arrays, one per hemisphere, located on the La Palma island (Spain) and in Paranal (Chile). We present here the optimised and final telescope arrays for both CTA sites, as well as their foreseen performance, resulting from the analysis of three different large-scale Monte Carlo productions.© 2019 ; We gratefully acknowledge financial support from the following agencies and organizations: State Committee of Science of Armenia, Armenia; The Australian Research Council, Astronomy Australia Ltd, The University of Adelaide, Australian National University, Monash University, The University of New South Wales, The University of Sydney, Western Sydney University, Australia; Federal Ministry of Science, Research and Economy, and Innsbruck University, Austria; Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq), Fundacao de Amparo a Pesquisa do Estado do Rio de Janeiro (FAPERJ), Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP), Ministry of Science, Technology, Innovations and Communications (MCTIC), Brasil; Ministry of Education and Science, National RI Roadmap Project D01-153/28.08.2018, Bulgaria; The Natural Sciences and Engineering Research Council of Canada and the Canadian Space Agency, Canada; CONICYT-Chile grants PFB-06, FB0821, ACT 1406, FONDECYT-Chile grants 3160153, 3150314, 1150411, 1161463, 1170171, Pontificia Universidad Catolica de Chile Vice-Rectory of Research internationalization grant under MINEDUC agreement PUC1566, Chile; ; Croatian Science Foundation, Rudjer Boskovic Institute, University of Osijek, University of Rijeka, University of Split, Faculty of Electrical Engineering, Mechanical Engineering and Naval Architecture, University of Zagreb, Faculty of Electrical Engineering and Computing, Croatia; Ministry of Education, Youth and Sports, MEYS LM2015046, LTT17006 and EU/MEYS CZ.02.1.01/0.0/0.0/16_013/0001403, CZ.02.1.01/0.0/0.0/17_049/0008422, Czech Republic; Ministry of Higher Education and Research, CNRS-INSU and CNRS-IN2P3, CEA-Irfu, ANR, Regional Council Ile-de France, Labex ENIGMASS, OSUG2020, P210 and OCEVU, France; Max Planck Society, BMBF, DESY, Helmholtz Association, Germany; Department of Atomic Energy, Department of Science and Technology, India; Istituto Nazionale di Astrofisica (INAF), Istituto Nazionale di Fisica Nucleare (INFN), MIUR, Istituto Nazionale di Astrofisica (INAF-OABRERA) Grant Fondazione Cariplo/Regione Lombardia ID 2014-1980/RST_ERC, Italy; ICRR, University of Tokyo, JSPS, MEXT, Japan; Netherlands Research School for Astronomy (NOVA), Netherlands Organization for Scientific Research (NWO), Netherlands; University of Oslo, Norway; Ministry of Science and Higher Education, DIR/WK/2017/12, the National Centre for Research and Development and the National Science Centre, UMO-2016/22/M/ST9/00583, Poland; Slovenian Research Agency, Slovenia, grants P1-0031, P1-0385, 10-0033, J1-9146; South African Department of Science and Technology and National Research Foundation through the South African Gamma-Ray Astronomy Programme, South Africa; MINECO National R+D+I, Severo Ochoa, Maria de Maeztu, CDTI, PAIDI, UJA, FPA2017-90566-REDC, Spain; Swedish Research Council, Royal Physiographic Society of Lund, Royal Swedish Academy of Sciences, The Swedish National Infrastructure for Computing (SNIC) at Lunarc (Lund), Sweden; Swiss National Science Foundation (SNSF), Ernest Boninchi Foundation, Switzerland; Durham University, Leverhulme Trust, Liverpool University, University of Leicester, University of Oxford, Royal Society, Science and Technology Facilities Council, UK; U.S. National Science Foundation, U.S.Department of Energy, Argonne National Laboratory, Barnard College, University of California, University of Chicago, Columbia University, Georgia Institute of Technology, Institute for Nuclear and Particle Astrophysics (INPAC-MRPI program), Iowa State University, the Smithsonian Institution, Washington University McDonnell Center for the Space Sciences, The University of Wisconsin and the Wisconsin Alumni Research Foundation, USA. The research leading to these results has received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreements no 262053 and no 317446. This project is receiving funding from the European Union's Horizon 2020 research and innovation programs under agreement no 676134. ; Peer Reviewed

We analyze the timing of photons observed by the MAGIC telescope during a flare of the active galactic nucleus Mkn 501 for a possible correlation with energy, as suggested by some models of quantum gravity (QG), which predict a vacuum refractive index ≃ 1 + (E / MQGn)n, n = 1, 2. Parametrizing the delay between γ-rays of different energies as Δ t = ± τl E or Δ t = ± τq E2, we find τl = (0.030 ± 0.012) s / GeV at the 2.5-σ level, and τq = (3.71 ± 2.57) × 10-6 s / GeV2, respectively. We use these results to establish lower limits MQG 1 > 0.21 × 1018 GeV and MQG 2 > 0.26 × 1011 GeV at the 95% C.L. Monte Carlo studies confirm the MAGIC sensitivity to propagation effects at these levels. Thermal plasma effects in the source are negligible, but we cannot exclude the importance of some other source effect. © 2008 Elsevier B.V. All rights reserved. ; The MAGIC Collaboration thanks the IAC for the excellent working conditions at the Observatorio del Roque de los Muchachos in La Palma and gratefully acknowledges the support of the German BMBF and MPG, the Italian INFN and the Spanish CICYT. This work was also supported by ETH Research Grant TH 34/04 3 and the Polish MNiI Grant 1P03D01028. The work of J.E. and N.E.M. was partially supported by the European Union through the Marie Curie Research and Training Network UniverseNet MRTN-CT-2006-035863, and that of D.V.N. by DOE grant DE-FG02-95ER40917. ; Peer Reviewed

PKS 1510-089 is a flat spectrum radio quasar strongly variable in the optical and GeV range. To date, very high-energy (VHE, > 100 GeV) emission has been observed from this source either during long high states of optical and GeV activity or during short flares. Aims. We search for low-state VHE gamma-ray emission from PKS 1510-089. We characterize and model the source in a broadband context, which would provide a baseline over which high states and flares could be better understood. Methods. PKS 1510-089 has been monitored by the MAGIC telescopes since 2012. We use daily binned Fermi-LAT flux measurements of PKS 1510-089 to characterize the GeV emission and select the observation periods of MAGIC during low state of activity. For the selected times we compute the average radio, IR, optical, UV, X-ray, and gamma-ray emission to construct a low-state spectral energy distribution of the source. The broadband emission is modeled within an external Compton scenario with a stationary emission region through which plasma and magnetic fields are flowing. We also perform the emission-model-independent calculations of the maximum absorption in the broad line region (BLR) using two different models. Results. The MAGIC telescopes collected 75 hr of data during times when the Fermi-LAT flux measured above 1 GeV was below 3? × 10 -8 ? cm -2 ? s -1 , which is the threshold adopted for the definition of a low gamma-ray activity state. The data show a strongly significant (9.5¿) VHE gamma-ray emission at the level of (4.27 ± 0.61 stat ) × 10 -12 ? cm -2 ? s -1 above 150 GeV, a factor of 80 lower than the highest flare observed so far from this object. Despite the lower flux, the spectral shape is consistent with earlier detections in the VHE band. The broadband emission is compatible with the external Compton scenario assuming a large emission region located beyond the BLR. For the first time the gamma-ray data allow us to place a limit on the location of the emission region during a low gamma-ray state of a FSRQ. For the used model of the BLR, the 95% confidence level on the location of the emission region allows us to place it at a distance > 74% of the outer radius of the BLR. © ESO 2018. ; 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, CSD2009-00064), and the Japanese JSPS and MEXT is gratefully acknowledged. This work was also supported by the Spanish Centro de Exce-lencia "Severo Ochoa" SEV-2012-0234 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 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, CNPq and FAPERJ. IA acknowledges support from a Ramón y Cajal grant of the Ministerio de Economía, Industria, y Competitividad (MINECO) of Spain. Acquisition and reduction of the POLAMI and 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. ; Peer Reviewed

The very high energy (VHE ¿ 100 GeV) -ray MAGIC observations of the blazar S4 0954+65, were triggered by an exceptionally high flux state of emission in the optical. This blazar has a disputed redshift of z = 0.368 or z ¿ 0.45 and an uncertain classification among blazar subclasses. The exceptional source state described here makes for an excellent opportunity to understand physical processes in the jet of S4 0954+65 and thus contribute to its classification. Methods. We investigated the multiwavelength (MWL) light curve and spectral energy distribution (SED) of the S4 0954+65 blazar during an enhanced state in February 2015 and have put it in context with possible emission scenarios. We collected photometric data in radio, optical, X-ray, and ¿-ray. We studied both the optical polarization and the inner parsec-scale jet behavior with 43 GHz data. Results. Observations with the MAGIC telescopes led to the first detection of S4 0954+65 at VHE. Simultaneous data with Fermi-LAT at high energy ¿-ray(HE, 100 MeV < E < 100 GeV) also show a period of increased activity. Imaging at 43 GHz reveals the emergence of a new feature in the radio jet in coincidence with the VHE flare. Simultaneous monitoring of the optical polarization angle reveals a rotation of approximately 100. Conclusions. The high emission state during the flare allows us to compile the simultaneous broadband SED and to characterize it in the scope of blazar jet emission models. The broadband spectrum can be modeled with an emission mechanism commonly invoked for flat spectrum radio quasars (FSRQs), that is, inverse Compton scattering on an external soft photon field from the dust torus, also known as external Compton. The light curve and SED phenomenology is consistent with an interpretation of a blob propagating through a helical structured magnetic field and eventually crossing a standing shock in the jet, a scenario typically applied to FSRQs and low-frequency peaked BL Lac objects (LBL). © ESO 2018. ; 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, CSD2009-00064), and the Japanese JSPS and MEXT is gratefully acknowledged. This work was also supported by the Spanish Centro de Excelencia "Severo Ochoa" SEV-2012-0234 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 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, CNPq, and FAPERJ. IA acknowledges support by a Ramón y Cajal grant of the Ministerio de Economía, Industria y Competitividad (MINECO) of Spain. The research at the IAA–CSIC was supported in part by the MINECO through grants AYA2016–80889–P, AYA2013–40825–P, and AYA2010–14844, and by the regional government of Andalucía through grant P09–FQM–4784. ; Peer Reviewed