On the origin of GeV spectral break for Fermi blazars: 3C 454.3
On the origin of GeV spectral break for Fermi blazars: 3C 454.3
复制标题
DOI：
10.1093/mnras/stab489
复制
发表时间：
2021-02
期刊：
影响因子：
--
通讯作者：
Shi-Ju Kang;Yonggang Zheng;Qingwen Wu;Liang Chen;Yue Yin
中科院分区：
文献类型：
--
作者：
Shi-Ju Kang;Yonggang Zheng;Qingwen Wu;Liang Chen;Yue Yin
Blazar 3C 454.3的GeV突变是Fermi-LAT发现的一个特殊观测特征。在光谱中的GeV突破的起源仍在争论中。为了探讨3C 454.3 GeV谱突变的可能来源，利用单区均匀轻子喷流模型和McFit技术拟合了3C 454.3的准同时多波段谱能量分布（SED）.考虑到观测到的W射线辐射，宽线区（BLR）和内部尘埃环的外边界被选择为在模型中贡献辐射作为外部种子光子到外部康普顿过程。两个组件的组合，即康普顿散射BLR和尘埃环面辐射，假设发射粒子的幂律分布被打破，提供了一个适当的拟合多波段SED的3C 454.3检测2008年8月3日9月2日，并解释了GeV的光谱断裂。我们认为，3C 454.3的光谱突变可能源于发射粒子能量分布的固有突变和Klein-Nishina效应。通过模型拟合获得的整个BLR *BLR的“外部”光子场的能量密度与BLR数据约束的能量密度之间进行了比较。从3C 454.3的W射线辐射区到中心黑洞的距离可以被限制在0.78pc（0.400 'BLR，BLR的大小）。
The GeV break in spectra of the blazar 3C 454.3 is a special observation feature that has been discovered by the Fermi-LAT. The origin of the GeV break in the spectra is still under debate. In order to explore the possible source of GeV spectral break in 3C 454.3, a one-zone homogeneous leptonic jet model, as well as the McFit technique are utilized for fitting the quasi-simultaneous multi-waveband spectral energy distribution (SED) of 3C 454.3. The outside border of the broad-line region (BLR) and inner dust torus are chosen to contribute radiation in the model as external, seed photons to the external-Compton process, considering the observed W-ray radiation. The combination of two components, namely the Compton-scattered BLR and dust torus radiation, assuming a broken power-law distribution of emitted particles, provides a proper fitting to the multi-waveband SED of 3C 454.3 detected 2008 Aug 3 Sept 2 and explains the GeV spectral break. We propose that the spectral break of 3C 454.3 may originate from an inherent break in the energy distribution of the emitted particles and the Klein-Nishina effect. A comparison is performed between the energy density of the ‘external’ photon field for the whole BLR *BLR achieved via model fitting and that constrained from the BLR data. The distance from the position of the W-ray radiation area of 3C 454.3 to the central black hole could be constrained at ∼ 0.78pc (∼ 4.00'BLR, the size of the BLR).