论文标题
在最亮的费米 - 拉特扁平光谱类星体中定位伽马射线发射区
Locating the gamma-ray emission region in the brightest Fermi-LAT Flat Spectrum Radio Quasars
论文作者
论文摘要
我们介绍了从Fermi大面积望远镜（LAT）检测到的最明亮平坦频谱类星体（FSRQ）的伽马射线通量（FSRQ）的时间和光谱分析，其目的是约束发射区域的位置。使用每个来源的两个最亮的耀斑提供的光子统计数据，我们发现了B2 1520+31，PKS 1502+106和PKS 1424-41的次小时变异性的证据，其余的来源显示了几个小时的时间表上的可变性。这些表明射流中极紧凑的区域的伽马射线发射可能与宽线区域内（BLR）内的发射兼容。耀斑光谱显示了在研究的18种耀斑中有7种频谱截止的证据，进一步支持了这些来源中BLR发射的论点。对冷却时间尺度的能量依赖性的研究发现了BLR起源和从分子圆环内部（MT）内发射的证据。但是，蒙特卡洛模拟表明，除3C 279、3C 454.3和4C 21.35以外，所有来源的高能量（VHE）发射与BLR起源不相容。所有使用的方法的结合发现表明，最亮的FSRQ中的伽马射线发射起源于整个射流的多个紧凑型发射区域，均来自BLR和MT。
We present a temporal and spectral analysis of the gamma-ray flux from nine of the brightest flat spectrum radio quasars (FSRQs) detected with the Fermi Large Area Telescope (LAT) during its first eight years of operation, with the aim of constraining the location of the emission region. Using the increased photon statistics provided from the two brightest flares of each source, we find evidence of sub-hour variability from B2 1520+31, PKS 1502+106 and PKS 1424-41, with the remaining sources showing variability on timescales of a few hours. These indicate gamma-ray emission from extremely compact regions in the jet, potentially compatible with emission from within the broad line region (BLR). The flare spectra show evidence of a spectral cut-off in 7 of the 18 flares studied, further supporting the argument for BLR emission in these sources. An investigation into the energy dependence of cooling timescales finds evidence for both BLR origin and emission from within the molecular torus (MT). However, Monte Carlo simulations show that the very high energy (VHE) emission from all sources except 3C 279, 3C 454.3 and 4C 21.35 is incompatible with a BLR origin. The combined findings of all the approaches used suggest that the gamma-ray emission in the brightest FSRQs originates in multiple compact emission regions throughout the jet, within both the BLR and the MT.
