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arXiv 1803.09856astro-ph.HE
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叶瓣优势射电星系3C 207的Fermi/LAT观测和可能的γ射线辐射区

Fermi/LAT observations of Lobe-dominant Radio Galaxy 3C 207 and Possible Radiation Region of the Gamma-Rays

Sheng-Chu Guo, Hai-Ming Zhang, Jin Zhang, En-Wei Liang

摘要:

3C 207是一个具有单侧喷流的瓣状射电星系,其亮节在射电、光学和X射线波段上都有kpc-Mpc尺度的分辨。Fermi/LAT证实它是一个伽马射线发射体,但由于Fermi/LAT的空间分辨率较低,无法确定伽马射线发射区是核心还是节点。我们提出了一个分析的费米/LAT数据在过去的9年。与地核的射电辐射和光辐射不同,γ射线辐射是稳定的,没有检测到超过2 σ置信水平的通量变化。这可能意味着伽马射线发射来自其结。我们收集的无线电,光学和X射线数据的knot-A,最近的结从核心在1角秒,并编制其光谱能量分布(SED)。虽然单区同步加速器+SSC+IC/CMB模型在假设结点A处于静止状态下可以再现射电-光学-X射线波段的SED,但预测的γ射线通量低于LAT观测值,推导的磁场强度偏离均分条件3个数量级。假设Knot-A是相对论运动的,在均分条件下,它从射电到γ射线波段的SED可以用单区同步加速器+SSC+IC/CMB模型很好地描述。这些结果可能表明,伽马射线发射可能是从结A通过IC/CMB过程和结应该有相对论运动。从我们的模型参数得到的喷流功率也大致与无线电数据估计的动能功率一致。

英文摘要:

3C 207 is a lobe-dominant radio galaxy with one sided jet and the bright knots in kpc-Mpc scale were resolved in the radio, optical and X-ray bands. It was confirmed as a gamma-ray emitter with Fermi/LAT, but it is uncertain whether the gamma-ray emission region is the core or knots due to the low spatial resolution of Fermi/LAT. We present an analysis of its Fermi/LAT data in the past 9 years. Different from the radio and optical emission from the core, it is found that the gamma-ray emission is steady without detection of flux variation over 2 sigma confidence level. This likely implies that the gamma-ray emission is from its knots. We collect the radio, optical, and X-ray data of knot-A, the closest knot from the core at 1 arcsec, and compile its spectral energy distribution (SED). Although the single-zone synchrotron+SSC+IC/CMB model by assuming knot-A at rest can reproduce the SED in the radio-optical-X-ray band, the predicted gamma-ray flux is lower than the LAT observations and the derived magnetic field strength deviates the equipartition condition with 3 orders of magnitude. Assuming that knot-A is relativistically moving, its SED from radio to gamma-ray bands would be well represented with the single-zone synchrotron+SSC+IC/CMB model under the equipartition condition. These results likely suggest that the gamma-ray emission may be from knot-A via the IC/CMB process and the knot should have relativistical motion. The jet power derived from our model parameters is also roughly consistent with the kinetic power estimated with the radio data.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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