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dc.contributor.authorConnolly, M.P.
dc.contributor.authorGillanders, Gary
dc.contributor.authorLang, Mark
dc.identifier.citationAbeysekara, AU,Archambault, S,Archer, A,Aune, T,Barnacka, A,Benbow, W,Bird, R,Biteau, J,Buckley, JH,Bugaev, V,Cardenzana, JV,Cerruti, M,Chen, X,Christiansen, JL,Ciupik, L,Connolly, MP,Coppi, P,Cui, W,Dickinson, HJ,Dumm, J,Eisch, JD,Errando, M,Falcone, A,Feng, Q,Finley, JP,Fleischhack, H,Flinders, A,Fortin, P,Fortson, L,Furniss, A,Gillanders, GH,Griffin, S,Grube, J,Gyuk, G,Hutten, M,Hakansson, N,Hanna, D,Holder, J,Humensky, TB,Johnson, CA,Kaaret, P,Kar, P,Kelley-Hoskins, N,Khassen, Y,Kieda, D,Krause, M,Krennrich, F,Kumar, S,Lang, MJ,Maier, G,McArthur, S,McCann, A,Meagher, K,Moriarty, P,Mukherjee, R,Nieto, D,De Bhroithe, AO,Ong, RA,Otte, AN,Park, N,Perkins, JS,Petrashyk, A,Pohl, M,Popkow, A,Pueschel, E,Quinn, J,Ragan, K,Ratliff, G,Reynolds, PT,Richards, GT,Roache, E,Rousselle, J,Santander, (2015) 'GAMMA-RAYS FROM THE QUASAR PKS 1441+25: STORY OF AN ESCAPE'. Astrophysical Journal Letters, 815 .en_IE
dc.description.abstractOutbursts from gamma-ray quasars provide insights on the relativistic jets of active galactic nuclei and constraints on the diffuse radiation fields that fill the universe. The detection of significant emission above 100 GeV from a distant quasar would show that some of the radiated gamma-rays escape pair-production interactions with low-energy photons, be it the extragalactic background light (EBL), or the radiation near the supermassive black hole lying at the jet's base. VERITAS detected gamma-ray emission up to similar to 200 GeV from PKS 1441+25 (z = 0.939) during 2015 April, a period of high activity across all wavelengths. This observation of PKS 1441+25 suggests that the emission region is located thousands of Schwarzschild radii away from the black hole. The gamma-ray detection also sets a stringent upper limit on the near-ultraviolet to near-infrared EBL intensity, suggesting that galaxy surveys have resolved most, if not all, of the sources of the EBL at these wavelengths.en_IE
dc.description.sponsorshipThis research is supported by grants from the U.S. Department of Energy Office of Science, the U.S. National Science Foundation and the Smithsonian Institution, and by NSERC in Canada, with additional support from NASA Swift GI grant NNX15AR38G.en_IE
dc.relation.ispartofAstrophysical Journal Lettersen
dc.subjectFERMI BLAZARSen_IE
dc.subjectCosmology: observationsen_IE
dc.subjectDiffuse radiationen_IE
dc.subjectGamma rays: galaxiesen_IE
dc.subjectQuasars: individual (PKS 1441+25-VER J1443+250)en_IE
dc.subjectRadiation mechanisms: non-thermalen_IE
dc.subjectExtragalactic background lighten_IE
dc.subjectComplete sampleen_IE
dc.titleGamma-rays from the quasar PKS 1441+25: story of an escapeen_IE
dc.local.contactMark Lang, School Of Physics, Room 147, Arts/Science Building, Nui Galway. 3241 Email:

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