High energy properties of the flat spectrum radio quasar 4C 50.11
High energy properties of the flat spectrum radio quasar 4C 50.11
复制标题
平谱射电类星体 4C 50.11 的高能量特性
DOI：
10.1088/1674-4527/18/16
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发表时间：
2017
影响因子：
1.8
通讯作者：
Zhongxiang Wang
中科院分区：
文献类型：
--
作者：
Jianeng Zhou;Vadakkumthani Jithesh;Liang Chen;Zhongxiang Wang
研究了红移z = 1.517的平谱射电类星体（FSRQ） 4C 50.11的γ射线和x射线性质。费米- lat数据表明，该源自2013年7月以来一直处于活跃状态。在这一活跃期，源发射的γ射线看起来更加坚硬，通量增加了三倍以上。我们分析了在活动状态下看到的两个不同的耀斑，发现变异短至几个小时。Swift-XRT数据显示，源在x射线能量上是可变的，但没有发现与γ射线活动相关的通量或光谱变化的证据。使用Swift-XRT和NuSTAR获得的宽带x射线光谱可以用破缺幂律模型很好地描述，在破缺能量以下具有非常平坦的光谱（γ1 ~ 0.1）。Ebreak ~ 2.1 keV, γ2 ~ 1.5以上。在~ 3 keV以下的光谱平坦化可能是由于光子发射电子居群的能量分布中的低能量截止。我们拟合了源在活动和静止状态下的宽带光谱能量分布。喷流的x射线和γ射线发射主要是由于逆康普顿散射过程，种子光子来自宽线区域，如果喷流主要由电子-质子对组成，则估计喷流大于吸积功率。
We investigate the γ-ray and X-ray properties of the flat spectrum radio quasar (FSRQ) 4C 50.11 at redshift z = 1.517. The Fermi-LAT data indicate that this source was in an active state since July 2013. During this active period, the source’s emission appeared harder in γ-rays, with the flux having increased by more than a factor of three. We analyze two distinct flares seen in the active state and find that the variability is as short as several hours. The Swift-XRT data show that the source was variable at X-ray energies, but no evidence is found for flux or spectral changes related to the γ-ray activity. The broad-band X-ray spectrum obtained with Swift-XRT and NuSTAR is described well by a broken power law model, with an extremely flat spectrum (γ1 ∼ 0.1) below the break energy,.Ebreak ∼ 2.1 keV, and γ2 ∼ 1.5 above the break energy. The spectral flattening below∼ 3 keV is likely due to the low energy cut-off in the energy distribution of the photon-emitting electron population. We fit the broad-band spectral energy distribution of the source during both the active and quiescent states. The X-ray and γ-ray emission from the jet is mainly due to the inverse-Compton scattering process, with seed photons provided from the broad line region, and the jet is estimated to be larger than the accretion power if the jet is mainly composed of electron-proton pairs.