Is the Core of M87 the Source of Its TeV Emission? Implications for Unified Schemes
Is the Core of M87 the Source of Its TeV Emission? Implications for Unified Schemes
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DOI：
10.1086/498714
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发表时间：
2005-10
期刊：
影响因子：
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通讯作者：
M. Georganopoulos;E. Perlman;D. Kazanas
中科院分区：
文献类型：
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作者：
M. Georganopoulos;E. Perlman;D. Kazanas
M87最近被证明是一个TeV源，可能是可变的。基于这一点和同期的光学和X射线监测，我们认为，TeV的排放源是M87的核心，而不是两个喷流结（HST-1和A）之一，与X射线亮度相媲美的核心。我们在核心的TeV排放模型的逆康普顿（IC）发射从基地的射流。齐次模型无法再现的光谱能量分布（SED），特别是TeV通量。它们也不符合BL Lacertae（BL）天体和FR I射电星系的统一方案。一个从洛伦兹因子Γ ~ 20减速到Γ ~ 5的喷流在~0.1 pc的长度上再现了观测到的M87核心的SED，当与视线对齐时，产生类似于TeV BL的SED。TeV通量在减速射流模型中成功地再现为上游康普顿（UC）散射，最近确定的发射机制，其中高能电子的上游更快的流upscatter的低能量光子产生的较慢的下游部分的流。
M87 has recently been shown to be a TeV source that is likely to be variable. Based on this and on contemporaneous optical and X-ray monitoring, we argue that the source of the TeV emission is the core of M87 and not one of two jet knots (HST-1 and A), with an X-ray brightness comparable to that of the core. We model the TeV emission in the core as inverse Compton (IC) emission from the base of the jet. Homogeneous models fail to reproduce the spectral energy distribution (SED) and, in particular, the TeV flux. They also fail to comply with the unified scheme of BL Lacertae (BL) objects and FR I radio galaxies. A jet that decelerates from a Lorentz factor Γ ~ 20 down to Γ ~ 5 over a length of ~0.1 pc reproduces the observed SED of the M87 core and, when aligned with the line of sight, produces a SED similar to those of TeV BLs. The TeV flux in the decelerating jet model is successfully reproduced as upstream Compton (UC) scattering, a recently identified emission mechanism, in which energetic electrons of the upstream faster flow upscatter the low-energy photons produced in the slower downstream part of the flow.