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Title: GAMMA-RAYS FROM THE QUASAR PKS 1441+25: STORY OF AN ESCAPE

Outbursts 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 ∼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.
Authors:
 [1] ;  [2] ; ; ;  [3] ;  [4] ;  [5] ; ;  [6] ;  [7] ;  [8] ;  [9] ;  [10] ;  [11] ;  [12] ;  [13] ;  [14] ;  [15] ; ;  [16] more »; ; ; ; ; ; ; « less
  1. Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112 (United States)
  2. Physics Department, McGill University, Montreal, QC H3A 2T8 (Canada)
  3. Department of Physics, Washington University, St. Louis, MO 63130 (United States)
  4. Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States)
  5. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
  6. Fred Lawrence Whipple Observatory, Harvard-Smithsonian Center for Astrophysics, Amado, AZ 85645 (United States)
  7. School of Physics, University College Dublin, Belfield, Dublin 4 (Ireland)
  8. Santa Cruz Institute for Particle Physics and Department of Physics, University of California, Santa Cruz, CA 95064 (United States)
  9. Department of Physics and Astronomy, Iowa State University, Ames, IA 50011 (United States)
  10. Institute of Physics and Astronomy, University of Potsdam, D-14476 Potsdam-Golm (Germany)
  11. Physics Department, California Polytechnic State University, San Luis Obispo, CA 94307 (United States)
  12. Astronomy Department, Adler Planetarium and Astronomy Museum, Chicago, IL 60605 (United States)
  13. School of Physics, National University of Ireland Galway, University Road, Galway (Ireland)
  14. Department of Astronomy, Yale University, New Haven, CT 06520-8101 (United States)
  15. Department of Physics and Astronomy, Purdue University, West Lafayette, IN 47907 (United States)
  16. School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States)
Publication Date:
OSTI Identifier:
22518651
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 815; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BLACK HOLES; COSMIC PHOTONS; COSMOLOGY; GALAXIES; GALAXY NUCLEI; GAMMA DETECTION; GAMMA RADIATION; GEV RANGE; JETS; PAIR PRODUCTION; PHOTON EMISSION; QUASARS; RELATIVISTIC RANGE; SCHWARZSCHILD RADIUS; ULTRAVIOLET RADIATION; UNIVERSE; VISIBLE RADIATION