WHY HAVE MANY OF THE BRIGHTEST RADIO-LOUD BLAZARS NOT BEEN DETECTED IN GAMMA-RAYS BY FERMI?
WHY HAVE MANY OF THE BRIGHTEST RADIO-LOUD BLAZARS NOT BEEN DETECTED IN GAMMA-RAYS BY FERMI?
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DOI：
10.1088/2041-8205/810/1/l9
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发表时间：
2015-07
期刊：
影响因子：
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通讯作者：
M. Lister;M. Aller;H. Aller;T. Hovatta;T. Hovatta;W. Max-Moerbeck;A. Readhead;J. Richards;E. Ros;E. Ros
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文献类型：
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作者：
M. Lister;M. Aller;H. Aller;T. Hovatta;T. Hovatta;W. Max-Moerbeck;A. Readhead;J. Richards;E. Ros;E. Ros
我们使用完整的Mojave 1.5Jy活动星系核(AGN)样本来检查北部天空中最亮的射电响亮的blazar的伽马射线探测统计数据。我们发现，在四年的3FGL目录期内，有23%的活动星系核在0.1GeV以上没有被费米-LAT探测到，部分原因是仪器选择效应，部分原因是它们的多普勒增强因子较低。光谱能量分布中具有同步加速器峰值的blazar也倾向于具有低于LAT的0.1GeV阈值的高能峰，因此不太可能被费米探测到。1.5Jy样品中未探测到的活动星系核也具有明显较低的15 GHz射电调制指数和视喷流速度，表明它们的多普勒因子低于平均水平。由于相对论多普勒增强的有效数量在伽马射线中得到增强(特别是在外部逆康普顿散射的情况下)，这使得它们不太可能出现在3FGL目录中。根据它们的观测特性，我们已经确定了几个明亮的射电选择的闪耀星，它们是未来费米探测的有力候选者。
We use the complete MOJAVE 1.5 Jy sample of active galactic nuclei (AGNs) to examine the gamma-ray detection statistics of the brightest radio-loud blazars in the northern sky. We find that 23% of these AGNs were not detected above 0.1 GeV by the Fermi-LAT during the four-year 3FGL catalog period partly because of an instrumental selection effect and partly due to their lower Doppler boosting factors. Blazars with synchrotron peaks in their spectral energy distributions located below 10 13.4 ?> Hz also tend to have high-energy peaks that lie below the 0.1 GeV threshold of the LAT, and are thus less likely to be detected by Fermi. The non-detected AGNs in the 1.5 Jy sample also have significantly lower 15 GHz radio modulation indices and apparent jet speeds, indicating that they have lower than average Doppler factors. Since the effective amount of relativistic Doppler boosting is enhanced in gamma-rays (particularly in the case of external inverse-Compton scattering), this makes them less likely to appear in the 3FGL catalog. Based on their observed properties, we have identified several bright radio-selected blazars that are strong candidates for future detection by Fermi.