Browsing Research Output by Subject "BL Lacertae objects: general"

Now showing items 1-10 of 16

    • The awakening of BL Lacertae: observations by Fermi, Swift and the GASP-WEBT 

      Raiteri, C.M.; Böttcher, M.; Villata, M.; D'Ammando, F.; Larionov, V.M. (Oxford University Press, 2013)
      Since the launch of the Fermi satellite, BL Lacertae has been moderately active at γ-rays and optical frequencies until 2011 May, when the source started a series of strong flares. The exceptional optical sampling achieved ...

    • Discovery of very high energy gamma rays from 1ES 1440 + 122 

      Archambault, S.; Böttcher, M.; Archer, A.; Barnacka, A.; Behera, B. (Oxford Univ Press, 2016)
      The BL Lacertae object 1ES 1440+122 was observed in the energy range from 85 GeV to 30 TeV by the VERITAS array of imaging atmospheric Cherenkov telescopes. The observations, taken between 2008 May and 2010 June and totalling ...

    • Discovery of very high energy γ-ray emission from the BL Lacertae object PKS 0301-243 with H.E.S.S. 

      Abramowski, A.; Böttcher, M.; Casanova, S.; Krüger, P.P.; Pekeur, N.W.; Sushch, I.; Venter, C.; Vorster, M.; H.E.S.S. Collaboration (EDP Sciences, 2013)
      The active galactic nucleus PKS 0301−243 (z = 0.266) is a high-synchrotron-peaked BL Lac object that is detected at high energies (HE, 100 MeV < E < 100 GeV) by Fermi/LAT. This paper reports on the discovery of PKS 0301−243 ...

    • Fermi/LAT counterparts of IceCube neutrinos above 100 TeV 

      Krauss, F.; Kreter, M.; Deoskar, K.; Baxter, C.; Kadler, M.; Fermi LAT (EDP Sciences, 2018)
      The IceCube Collaboration has published four years of data and the observed neutrino flux is significantly in excess of the expected atmospheric background. Due to the steeply falling atmospheric background spectrum, events ...

    • First NuSTAR observations of Mrk 501 within a radio to TeV multi-instrument campaign 

      Furniss, A.; Böttcher, M.; Noda, K.; Boggs, S.; Chiang, J. (American Astronomical Society, 2015)
      We report on simultaneous broadband observations of the TeV-emitting blazar Markarian 501 between 2013 April 1 and August 10, including the first detailed characterization of the synchrotron peak with Swift and NuSTAR. During ...

    • Long term observations of B2 1215+30 with Veritas 

      Aliu, E.; Böttcher, M.; Archambault, S.; Arlen, T.; Aune, T. (IOP Science, 2013)
      We report on VERITAS observations of the BL Lac object B2 1215+30 between 2008 and 2012. During this period, the source was detected at very high energies (VHEs; E > 100 GeV) by VERITAS with a significance of 8.9σ and ...

    • Measurement of the EBL spectral energy distribution using the VHE γ-ray spectra of H.E.S.S. blazars 

      Abdalla, H.; Barnard, M.; Böttcher, M.; Davids, I.D.; Garrigoux, T.; Ivascenko, A.; Krüger, P.P.; Pekeur, N.W.; Richter, S.; 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 (EDP Sciences, 2017)
      Very high-energy γ rays (VHE, E ≳ 100 GeV) propagating over cosmological distances can interact with the low-energy photons of the extragalactic background light (EBL) and produce electron-positron pairs. The transparency ...

    • Measurement of the extragalactic background light imprint on the spectra of the brightest blazars observed with H.E.S.S. 

      Abramowski, A.; Casanova, S.; Pekeur, N.W.; Sheidaei, F.; Venter, C.; Vorster, M. (EDP Sciences, 2013)
      The extragalactic background light (EBL) is the diffuse radiation with the second highest energy density in the Universe after the cosmic microwave background. The aim of this study is the measurement of the imprint of the ...

    • Multiband optical-NIR variability of blazars on diverse time-scales 

      Agarwal, Aditi; Böttcher, M.; Gupta, Alok C.; Bachev, R.; Strigachev, A. (Oxford University Press, 2015)
      To search for optical variability on awide range of time-scales,we have carried out photometric monitoring of two flat spectrum radio quasars, 3C 454.3 and 3C 279, plus one BL Lac, S5 0716+714, all of which have been ...

    • Multiwavelength observations and modeling of 1ES 1959+650 in low flux state 

      Aliu, E.; Böttcher, M.; Archambault, S.; Arlen, T.; Aune, T. (IOP Science, 2013)
      We report on the VERITAS observations of the high-frequency peaked BL Lac object 1ES 1959+650 in the period 2007–2011. This source is detected at TeV energies by VERITAS at 16.4 standard deviation (σ) significance in 7.6 ...