RT Journal Article
T1 Very high energy γ-rays from the universe's middle age: detection of the z = 0.940 blazar pks 1441+25 with MAGIC
A1 Barrio Uña, Juan Abel
A1 Bonnefoy, Simon Francois Albert
A1 Contreras González, José Luis
A1 Carreto Fidalgo, David Friedrich
A1 Fonseca González, María Victoria
A1 López Moya, Marcos
A1 Nievas Rosillo, Miguel
A1 Satalecka, Konstanzja
AB The flat-spectrum radio quasar PKS 1441+25 at a redshift of z = 0.940 is detected between 40 and 250 GeV with a significance of 25.5σ using the MAGIC telescopes. Together with the gravitationally lensed blazar QSO B0218+357 (z = 0.944), PKS 1441+25 is the most distant very high energy (VHE) blazar detected to date. The observations were triggered by an outburst in 2015 April seen at GeV energies with the Large Area Telescope on board Fermi. Multi-wavelength observations suggest a subdivision of the high state into two distinct flux states. In the band covered by MAGIC, the variability timescale is estimated to be 6.4 ± 1.9 days. Modeling the broadband spectral energy distribution with an external Compton model, the location of the emitting region is understood as originating in the jet outside the broad-line region (BLR) during the period of high activity, while being partially within the BLR during the period of low (typical) activity. The observed VHE spectrum during the highest activity is used to probe the extragalactic background light at an unprecedented distance scale for ground-based gamma-ray astronomy.
PB IOP Publishing
SN 2041-8205
YR 2015
FD 2015-12-20
LK https://hdl.handle.net/20.500.14352/24397
UL https://hdl.handle.net/20.500.14352/24397
LA eng
NO © IOP Publishing.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 (FPA2012-39502) and MECD (FPU13/ 00618), and the Japanese JSPS, and MEXT is gratefully acknowledged. This work was also supported by the Centro de Excelencia Severo Ochoa SEV-2012-0234, CPAN CSD2007- 00042, and MultiDark CSD2009-00064 projects of the Spanish Consolider-Ingenio 2010 programme, by grant 268740 of the Academy of Finland, by the Croatian Science Foundation (HrZZ) Project 09/176 and the University of Rijeka Project 13.12.1.3.02, by the DFG Collaborative Research Centers SFB823/C4 and SFB876/C3, and by the Polish MNiSzW grant 745/N-HESS-MAGIC/2010/0.The Fermi-LAT Collaboration acknowledges support for LAT development, operation and data analysis from NASA and DOE (United States), CEA/Irfu and IN2P3/CNRS (France), ASI and INFN (Italy), MEXT, KEK, and JAXA (Japan), and the K.A. Wallenberg Foundation, the Swedish Research Council and the National Space Board (Sweden). Science analysis support in the operations phase from INAF (Italy) and CNES (France) is also gratefully acknowledged. We thank the Swift team duty scientists and science planners. L.P. acknowledges the PRIN-INAF 2014 financial support.
NO Ministerio de Economía y Competitividad (MINECO), España
NO Webauftritts des Bundesministeriums für Bildung und Forschung (BMBF), Alemania
NO Max-Planck-Gesellschaft (MPG), Alemania
NO Istituto Nazionale di Fisica Nucleare (INFN), Italia
NO Istituto Nazionale di Astrofisica (INAF), Italia
NO Swiss National Fund (SNF), Suiza
NO Fondo Europeo de Desarrollo  Regional (FEDER), UE
NO Unión Europea (UE)
NO Ministerio de Educación, Cultura y Deporte (MECD), España
NO Programa Nacional de Formación de Profesorado Universitario (FPU), MECD
NO Japan Society for the Promotion of Science (JSPS), Japón
NO Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japón
NO Centro de Excelencia Severo Ochoa
NO Centro Nacional de Física de Partículas, Astropartículas y Nuclear (CPAN), España
NO Programa Consolider-Ingenio 2010
NO Academy of Finland
NO Croatian Science Foundation (HrZZ), Croacia
NO University of Rijeka, Croacia
NO Deutsche Forschungsgemeinschaft = Fundación Alemana de Investigación Científica (DFG)
NO DFG Collaborative Research Centres, Alemania
NO MNiSzW, Polonia
NO National Aeronautics and Space Administration (NASA)
NO Department of Energy (DOE)
NO Institut de recherche sur les lois fondamentales de l'Univers (Irfu), Francia
NO IRFU CEA-Saclay laboratory, Francia
NO Institut national de physique nucléaire et de physique des particules (IN2P3), Francia
NO Centre national de la recherche scientifique (CNRS)
NO Agenzia Spaziale Italiana (ASI)
NO Energy Accelerator Research Organization (KEK), Japón
NO Japan Aerospace Exploration Agency (JAXA), Japón
NO K.A. Wallenberg Foundation
NO Swedish Research Council and the National Space Board (Suecia)
DS Docta Complutense
RD 18 abr 2025