Superluminal Radio Features in the M87 Jet and the Site of Flaring TeV Gamma-ray Emission

May, 2007
4 pages
Published in:
  • Astrophys.J.Lett. 663 (2007) L65
e-Print:

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20072011201520192023051015
Abstract: (arXiv)
Superluminal motion is a common feature of radio jets in powerful gamma-ray emitting active galactic nuclei. Conventionally, the variable emission is assumed to originate near the central supermassive black-hole where the jet is launched on parsec scales or smaller. Here, we report the discovery of superluminal radio features within a distinct flaring X-ray emitting region in the jet of the nearby radio galaxy M87 with the Very Long Baseline Array. This shows that these two phenomenological hallmarks -- superluminal motion and high-energy variability -- are associated, and we place this activity much further (>=120 pc) from the ``central engine'' in M87 than previously thought in relativistic jet sources. We argue that the recent excess very high-energy TeV emission from M87 reported by the H.E.S.S. experiment originates from this variable superluminal structure, thus providing crucial insight into the production region of gamma-ray emission in more distant blazars.
  • Galaxies: active
  • galaxies: jets
  • galaxies: individual (M87)
  • radio continuum: galaxies
  • radiation mechanisms: nonthermal
  • X-ray: cosmic radiation
  • gamma ray: cosmic radiation
  • cosmic radiation: particle source
  • radiation: emission
  • effect: superluminal