Relativistic Outflow Drives Gamma-Ray Emission in 3C345
Relativistic Outflow Drives Gamma-Ray Emission in 3C345
复制标题
DOI：
10.1051/0004-6361/201117705
复制
发表时间：
2011-11
期刊：
影响因子：
--
通讯作者：
F. Schinzel;A. Lobanov;G. Taylor;S. Jorstad;A. Marscher;J. Zensus
中科院分区：
文献类型：
--
作者：
F. Schinzel;A. Lobanov;G. Taylor;S. Jorstad;A. Marscher;J. Zensus
目的：根据费米-LAT最初20个月的数据和光学监测，3C345最近被确认为伽马射线发射器。本文研究了3C345的伽马射线和光学变率与其微秒级射电发射特性之间的关系。方法：3C345的Fermi-LAT数据覆盖0.1-300GeV的能量范围，结合2008年1月至2010年3月在43.2 GHz对该天体进行的32个甚长基线阵列观测。结果：VLBA数据揭示了高达5毫角秒的尺度上流动的形态和运动学(ma；出射的线性距离380秒)。沿喷流测得的亮温度T_b(R)首先与距离r^-(0.95+/-0.69)成正比，然后在约0.3 Ma处出现突变，在较大间隔时，T_b(R)与r^-(4.11+/-0.85)成正比。伽马射线、光学和微秒级射电发射的变化在整个甚低层大气管理局监测期间都显示出类似的长期趋势。较短时间尺度上的伽马射线和光学变化与喷流在约0.3 Ma(约23秒，去投影)尺度上的结构变化有关，而伽马射线和光学耀斑可能与气流中四个不同的超光速分量的演化有关。结论：观测表明，伽马射线辐射的静止和耀斑成分都产生在~23pC的喷流区域。这个区域可能标志着流的康普顿损失主导区，它的很大程度上可能有利于类星体3C345相对论喷流中产生伽马射线的同步加速器自康普顿机制。
Aims: 3C345 was recently identified as a gamma-ray emitter, based on the first 20 months of Fermi-LAT data and optical monitoring. In this paper, a connection between the gamma-ray and optical variability of 3C345 and properties of its parsec-scale radio emission is investigated. Methods: The Fermi-LAT data of 3C345, covering an energy range of 0.1-300 GeV, were combined with 32 Very Long Baseline Array observations of the object made at 43.2 GHz in the period of January 2008 - March 2010. Results: The VLBA data reveal morphology and kinematics of the flow on scales of up to ~5 milliarcseconds (mas; deprojected linear distances of 380 parsecs). The brightness temperature, T_b(r), measured along the jet first decreases with distance proportional to r^-(0.95 +/-0.69) and later exhibits a break at ~0.3 mas, with T_b(r) proportional to r^-(4.11 +/-0.85) at larger separations. Variations of the gamma-ray, optical and parsec-scale radio emission show a similar long-term trend persistent during the entire VLBA monitoring period. The gamma-ray and optical variations on shorter time scales are related to structural changes in the jet on scales of ~0.3 mas (~23 parsecs, deprojected), with the gamma-ray and optical flares possibly related to the evolution of four distinct superluminal components identified in the flow. Conclusions: The observations indicate that both the quiescent and flaring components of the gamma-ray emission are produced in a region of the jet of ~23 pc in extent. This region may mark the Compton-loss dominated zone of the flow and its large extent may favor the synchrotron self-Compton mechanism for gamma-ray production in the relativistic jet of the quasar 3C345.