M87 as a misaligned Synchrotron-Proton Blazar

Abstract

The giant radio galaxy M87 is usually classified as a Fanaroff-Riley class I source, suggesting that M87 is a mis-aligned 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 of M87 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 gamma-ray power output is dominated either by mu/pi-synchrotron or proton synchrotron radiation depending on whether the primary electron synchrotron component peaks at low or high energies, respectively. The predicted gamma-ray luminosity peaks at around 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. (abridged)

12 pages, 4 figures, accepted for publication in A&A

References in corpus (8)

• BL Lac Objects in the Synchrotron Proton Blazar Model
• A Proton Synchrotron Blazar Model for Flaring in Markarian~501
• VERITAS: the Very Energetic Radiation Imaging Telescope Array System
• EGRET upper limits on the high-energy gamma-ray emission of galaxy clusters
• Is the Giant Radio Galaxy M87 a TeV Gamma-Ray Emitter?
• Flaring X-ray Emission from HST-1, a Knot in the M87 Jet
• TeV gamma rays and cosmic rays from the nucleus of M87, a mis-aligned BL Lac object
• Small-Angle Scattering and Diffusion: Application to Relativistic Shock Acceleration

Cited by in corpus (4)

• The Physics of Gamma-Ray Bursts and Relativistic Jets
• Spectral and temporal signatures of ultrarelativistic protons in compact sources
• TeV gamma-rays from UHECR interactions in AGN cores: Lessons from Centaurus A
• Hadronic Models for LAT Prompt Emission Observed in Fermi Gamma-Ray Bursts