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https://hdl.handle.net/2440/50830
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Type: | Journal article |
Title: | Upper limits from HESS active galactic nuclei observations in 2005-2007 |
Author: | Aharonian, F. Akhperjanian, A. Barres de Almaida, U. Bazer-Bachi, A. Behera, B. Beilicke, M. Benbow, W. Bernlohr, K. Boisson, C. Bolz, O. Borrel, V. Braun, I. Brion, E. Brown, A. Buhler, R. Bulik, T. Busching, I. Boutelier, T. Carrigan, S. Chadwick, P. et al. |
Citation: | Astronomy and Astrophysics: a European journal, 2008; 478(2):387-393 |
Publisher: | EDP Sciences |
Issue Date: | 2008 |
ISSN: | 0004-6361 1432-0746 |
Statement of Responsibility: | F. Aharonian, A. G. Akhperjanian, U. Barres de Almeida, A. R. Bazer-Bachi, B. Behera ... Gavin P. Rowell ... et al. |
Abstract: | The γ-ray spectrum of the low-frequency-peaked BL Lac (LBL) object AP Librae is studied, following the discovery of very-high-energy (VHE; E > 100 GeV) γ-ray emission up to the TeV range by the H.E.S.S. experiment. Thismakes AP Librae one of the few VHE emitters of the LBL type. The measured spectrum yields a flux of (8.8 ± 1.5stat ± 1.8sys) × 10−12 cm−2 s−1 above 130 GeV and a spectral index ofΓ = 2.65±0.19stat ± 0.20sys . This study also makes use of Fermi-LAT observations in the high energy (HE, E > 100 MeV) range, providing the longest continuous light curve (5 years) ever published on this source. The source underwent a flaring event between MJD 56 306–56 376 in the HE range, with a flux increase of a factor of 3.5 in the 14 day bin light curve and no significant variation in spectral shape with respect to the low-flux state. While the H.E.S.S. and (low state) Fermi-LAT fluxes are in good agreement where they overlap, a spectral curvature between the steep VHE spectrum and the Fermi-LAT spectrum is observed. The maximum of the γ-ray emission in the spectral energy distribution is located below the GeV energy range. |
Keywords: | galaxies: active gamma rays: observations |
Description: | Copyright © ESO 2008 |
Rights: | © ESO 2008 |
DOI: | 10.1051/0004-6361:20078604 |
Published version: | http://dx.doi.org/10.1051/0004-6361:20078604 |
Appears in Collections: | Aurora harvest 5 Chemistry and Physics publications |
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hdl_50830.pdf | Published version | 126.61 kB | Adobe PDF | View/Open |
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