Please use this identifier to cite or link to this item:
https://hdl.handle.net/2440/18081
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Type: | Journal article |
Title: | M87 as a misaligned synchrotron-proton blazar |
Author: | Reimer, A. Protheroe, R. Donea, A. |
Citation: | Astronomy and Astrophysics: a European journal, 2004; 419(1):89-98 |
Publisher: | E D P Sciences |
Issue Date: | 2004 |
ISSN: | 0004-6361 1432-0746 |
Statement of Responsibility: | A. Reimer, R. J. Protheroe, and A.-C. Donea |
Abstract: | The giant radio galaxy M87 is usually classified as a Fanaroff-Riley class I source, suggesting that M87 is a misaligned BL Lac object. Its unresolved nuclear region emits strong non-thermal emission from radio to X-rays which has been interpreted as synchrotron radiation. In an earlier paper we predicted M87 as a source of detectable gamma ray emission in the context of the hadronic Synchrotron-Proton Blazar (SPB) model. The subsequent tentative detection of TeV energy photons by the HEGRA-telescope array would, if confirmed, make it the first radio galaxy to be detected at TeV-energies. We discuss the emission from the unresolved nuclear region ofM87 in the context of the SPB model, and give examples of possible model representations of its non-simultaneous spectral energy distribution. The low-energy component can be explained as synchrotron radiation by a primary relativistic electron population that is injected together with energetic protons into a highly magnetized emission region. We find that the γ-ray power output is dominated either by μ± /π± synchrotron or proton synchrotron radiation depending on whether the primary electron synchrotron component peaks at low or high energies, respectively. The predicted γ-ray luminosity peaks at ∼100 GeV at a level comparable to that of the low-energy hump, and this makes M87 a promising candidate source for the newly-commissioned high-sensitivity low-threshold Cherenkov telescopes H.E.S.S., VERITAS, MAGIC and CANGAROO III. Because of its proximity, the high-energy spectrum of M87 is unaffected by absorption in the cosmic infrared (IR) background radiation field, and could therefore serve as a template spectrum for the corresponding class of blazar if corrected for mis-alignment effects. This could significantly push efforts to constrain the cosmic IR radiation field through observation of more distant TeV-blazars, and could have a strong impact on blazar emission models. If M87 is a misaligned BL-Lac object and produces TeV-photons as recently detected by the HEGRA-array, in the context of the SPB model it must also be an efficient proton accelerator. |
Keywords: | galaxies: active galaxies: individual: M87 gamma rays: theory radiation mechanisms: non-thermal |
Rights: | © The European Southern Observatory 2004 |
DOI: | 10.1051/0004-6361:20034231 |
Published version: | https://www.aanda.org/articles/aa/abs/2004/19/aa0231/aa0231.html |
Appears in Collections: | Aurora harvest 2 Physics publications |
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File | Description | Size | Format | |
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hdl_18081.pdf | Published version | 261.59 kB | Adobe PDF | View/Open |
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