Recent Progress in Understanding the Large Scale Jets of Powerful Quasars
Recent Progress in Understanding the Large Scale Jets of Powerful Quasars
复制标题
了解强大类星体大规模喷流的最新进展
DOI：
--
复制
发表时间：
2016
期刊：
影响因子：
--
通讯作者：
E. Perlman
中科院分区：
文献类型：
--
作者：
M. Georganopoulos;E. Meyer;E. Perlman
我们对 kpc 尺度类星体喷流物理学的理解似乎已趋于一致，其中这些喷流在 kpc 尺度上与在靠近中心黑洞的亚 PC 尺度上具有高度相对论性。在这些距离上保持 10-20 左右的体洛伦兹因子 (Г) 意味着射流功率相当于或高于其爱丁顿光度。我们最近开始挑战这一范式，该范式的建立是为了将许多类星体喷流结的令人惊讶的明亮 X 射线发射解释为宇宙微波背景 (IC/CMB) 的逆康普顿散射。我们已经证明，原型喷流 3C 273 和 PKS 0637-752 的结 X 射线发射不是由 IC/CMB 引起的。由于 IC/CMB 不受欢迎，对 X 射线的另一种解释是来自原位加速至 ∼100 TeV 的第二组电子的同步辐射。这些结果是解决强大类星体喷流中 X 射线发射性质这一长期存在问题的第一步。需要对几乎所有 X 射线探测到的大型类星体喷流进行全面的观测和理论工作，以在更大的群体上测试 IC/CMB 模型，以研究速度较慢的喷流作为极其高效的加速器的影响。一个令人着迷的例子是，与普遍的看法相反，这些源的大型射流的总辐射功率与类星体核心的总辐射功率相当。更重要的是，这些（以前被认为是 TeV 安静）类星体喷流的角积分 TeV 输出可能使它们成为活动星系核（AGN）中的主导类别，超过了所谓的 TeV 耀变体的 TeV 输出。
Our understanding of the physics of kpc-scale quasar jets had seemed to converge to a paradigm in which these jets are as highly relativistic on the kpc scale as they are on sub-pc scales close to the central black hole. Retaining bulk Lorentz factors (Γ) on the order of 10–20 at these distances implies a jet power comparable to or higher than their Eddington luminosity. We recently started challenging this paradigm, which was put in place to explain the surprisingly bright X-ray emission of the knots of many quasar jets as inverse Compton scattering off the cosmic microwave background (IC/CMB). We have shown that the knot X-ray emission of the archetypical jets 3C 273 and PKS 0637-752 is not due to IC/CMB. With IC/CMB disfavored, an alternative interpretation for the X-rays is synchrotron radiation from a second population of electrons accelerated in situ up to ∼100 TeV. These results are the first step towards resolving the long-standing issue of the nature of the X-ray emission in powerful quasar jets. Comprehensive observational and theoretical work on essentially all X-ray-detected large-scale quasar jets to test the IC/CMB model over a much larger population needs to be done to examine the implications of slower jets that are extremely efficient accelerators. A fascinating case can be made that—contrary to popular belief—the total radiative power of the large-scale jet of these sources is comparable to that of the quasar core. Even more so, the angle-integrated TeV output of these (previously thought TeV-quiet) quasar jets likely makes them the dominant class among active galactic nuclei (AGN), exceeding the TeV production of so-called TeV blazars.