Possible High Energy Emission from the Hot Spot of Pictor A
Pictor A is a nearby Fanaroff-Riley class Ⅱ (FR Ⅱ) radio galaxy with a bright hot spot, the western hot spot. We use a single-zone synchrotron + synchrotron self-Compton (SSC) model and a multi-zone synchrotron + SSC model to fit the observed spectral energy distribution (SED) of the hot spot from the radio to X ray band, respectively. Our results show that in the case of a much weaker magnetic field strength comparing to the equipartition magnetic field, both the single-zone and multi-zone models can fit the SED. However, the single-zone model poorly fits the near-violet data, and the multi-zone model significantly improves the fit. The two models predict Pictor A as a GeV-TeV source, which could be marginally detectable with Fermi/LAT and HESS. We emphasize that under the equipartition condition, the SED can also be fit with the multi-zone model. In this scenario, the predicted fiux of the emission at > 1022 Hz is too weak to be detected.
FR Ⅱ radio galaxies individual Pictor A - gamma rays theory -radiation mechanisms nonthermal - X-rays hot spot
J. Zhang J. M. Bai X. Yang
National Astronomical Observatories/Yunnan Observatory,Chinese Academy of Scientes, Kunming,China T National Astronomical Observatories/Yunnan Observatory,Chinese Academy of Scientes,Kunming,China
国际会议
The 10th Asian-Pacific Regional International Astronomical Union Meeting(第十届亚洲及太平洋地区天文学大会 APRIM)
昆明
英文
280-281
2008-08-03（万方平台首次上网日期，不代表论文的发表时间）