Browsing by Subject "Gamma-rays: galaxies"

Now showing items 1-5 of 5

    • The 2012 flare of PG 1553+113 seen with H.E.S.S. and Fermi-LAT 

      Abramowski, A.; Böttcher, M.; Davids, I.D.; Ivascenko, A.; Krüger, P.P.; Pekeur, N.W.; Spanier, F.; Sushch, I.; Venter, C.; Vorster, M.; H.E.S.S. Collaboration (IOP Publishing, 2015)
      Very high energy (VHE, E > 100 GeV) γ-ray flaring activity of the high-frequency peaked BL Lac object PG 1553+113 has been detected by the H.E.S.S. telescopes. The flux of the source increased by a factor of 3 during the ...

    • Attenuation of TeV γ-rays by the starlight photon field of the host galaxy 

      Zacharias, Michael; Chen, Xuhui; Wagner, Stefan J. (Oxford Univ Press, 2017)
      The absorption of TeV γ-ray photons produced in relativistic jets by surrounding soft photon fields is a long-standing problem of jet physics. In some cases, the most likely emission site close to the central black hole ...

    • H.E.S.S. discovery of very high energy γ-ray emission from PKS 0625−354 

      Abdalla, H.; Barnard, M.; Davids, I.D.; Garrigoux, T.; Ivascenko, A.; Pekeur, N.W.; Seyffert, A.S.; Spanier, F.; Sushch, I.; Van der Walt, D.J.; Van Rensburg, C.; Venter, C.; Wadiasingh, Z.; H.E.S.S. Collaboration (Oxford Univ Press, 2018)
      PKS 0625−354 (z = 0.055) was observed with the four High Energy Stereoscopic System (H.E.S.S.) telescopes in 2012 during 5.5 h. The source was detected above an energy threshold of 200 GeV at a significance level of 6.1σ. ...

    • H.E.S.S. observations of the flaring gravitationally lensed galaxy PKS 1830-211 

      Abdalla, H.; Arcaro, C.; Backes, M.; Barnard, M.; Böttcher, M.; Chand, T.; Chandra, S.; Ndiyavala, H.; Schutte, H.; Seyffert, A.S.; Van der Walt, D.J.; Van Rensburg, C.; Venter, C.; Wadiasingh, Z.; Zacharias, M.; H.E.S.S. Collaboration (Oxford Univ Press, 2019)
      PKS 1830–211 is a known macrolensed quasar located at a redshift of z = 2.5. Its high-energy gamma-ray emission has been detected with the Fermi-Large Area Telescope (LAT) instrument and evidence for lensing was obtained ...

    • VHE γ-ray discovery and multiwavelength study of the blazar 1ES 2322-409 

      Abdalla, H.; Arcaro, C.; Backes, M.; Barnard, M.; Böttcher, M.; Chandra, S.; Garrigoux, T.; Krüger, P.P.; Ndiyavala, H.; Seyffert, A.S.; Spanier, F.; Sushch, I.; Van der Walt, D.J.; Van Rensburg, C.; Venter, C.; Wadiasingh, Z.; Zacharias, M.; H.E.S.S. Collaboration (Oxford Univ Press, 2019)
      A hotspot at a position compatible with the BL Lac object 1ES 2322−409 was serendipitously detected with H.E.S.S. during observations performed in 2004 and 2006 on the blazar PKS 2316−423. Additional data on 1ES 2322−409 ...