RT Journal Article T1 New Hard-TeV Extreme Blazars Detected with the MAGIC Telescopes* A1 Barrio Uña, Juan Abel A1 Contreras González, José Luis A1 Fidalgo, David Friedrich Carreto A1 Fonseca González, María Victoria A1 Hoang, Kim Dinh A1 López Moya, Marcos A1 Morcuende, D. A1 Peñil Del Campo, Pablo A1 Saha, Lab AB Extreme high-frequency-peaked BL Lac objects (EHBLs) are blazars that exhibit extremely energetic synchrotron emission. They also feature nonthermal gamma-ray emission whose peak lies in the very high-energy (VHE, E > 100 GeV) range, and in some sources exceeds 1 TeV: this is the case for hard-TeV EHBLs such as 1ES 0229+200. With the aim of increasing the EHBL population, 10 targets were observed with the MAGIC telescopes from 2010 to 2017, for a total of 265 hr of good-quality data. The data were complemented by coordinated Swift observations. The X-ray data analysis confirms that all but two sources are EHBLs. The sources show only a modest variability and a harder-when-brighter behavior, typical for this class of objects. At VHE gamma-rays, three new sources were detected and a hint of a signal was found for another new source. In each case, the intrinsic spectrum is compatible with the hypothesis of a hard-TeV nature of these EHBLs. The broadband spectral energy distributions (SEDs) of all sources are built and modeled in the framework of a single-zone, purely leptonic model. The VHE gamma-ray-detected sources were also interpreted with a spine-layer model and a proton synchrotron model. The three models provide a good description of the SEDs. However, the resulting parameters differ substantially in the three scenarios, in particular the magnetization parameter. This work presents the first mini catalog of VHE gamma-ray and multiwavelength observations of EHBLs. PB University Chicago Press SN 0067-0049 YR 2020 FD 2020-03 LK https://hdl.handle.net/20.500.14352/6211 UL https://hdl.handle.net/20.500.14352/6211 LA eng NO © 2020. The American Astronomical Society. All rights reserved. Artículo firmado por 177 autores. We would like to thank the Instituto de Astrofísica 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, FPA 2015-68378-P, FPA2017-82729-C6-2-R, FPA2015-69210-C64-R, FPA2015-69210-C6-6-R, AYA2015-71042-P, AYA201676012-C3-1-P, ESP2015-71662-C2-2-P, FPA2017-90566-RE DC), the Indian Department of Atomic Energy, the Japanese JSPS and MEXT, the Bulgarian Ministry of Education and Science, National RI Roadmap Project DO1-153/28.08.2018, and the Academy of Finland grant nr. 320045 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 "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.; E.P. has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No. 664931.; M.C. has received financial support through the Postdoctoral Junior Leader Fellowship Programme from la Caixa Banking Foundation, grant No. LCF/BQ/LI18/11630012. NO Unión Europea. Horizonte 2020 NO Ministerio de Economía y Competitividad (MINECO)/FEDER NO Centro de Excelencia Severo Ochoa NO Unidad de Excelencia Maria de Maeztu NO German BMBF Federal Ministry of Education & Research (BMBF) NO German MPG NO Italian INFN Istituto Nazionale di Fisica Nucleare NO Italian INAF Istituto Nazionale Astrofisica NO Swiss National Fund SNF Swiss National Science Foundation (SNSF) NO Indian Department of Atomic Energy NO Japanese JSPS Ministry of Education, Culture, Sports, Science and Technology, Japan (MEXT) Japan Society for the Promotion of Science NO Japanese MEXTMinistry of Education, Culture, Sports, Science and Technology, Japan (MEXT) NO Bulgarian Ministry of Education and Science NO National RI Roadmap Project NO Academy of FinlandAcademy of Finland NO Croatian Science Foundation (HrZZ) NO University of Rijeka NO DFG Collaborative Research Centers NO Polish National Research Centre NO Brazilian MCTIC NO Brazilian CNPq National Council for Scientific and Technological Development (CNPq) NO Brazilian FAPERJ NO La Caixa Banking Foundation DS Docta Complutense RD 10 abr 2025