延迟放大和相对论喷流的出现
Retardation magnification and the appearance of relativistic jets
摘要：
由于甚大阵、哈勃太空望远镜和钱德拉X射线天文台等高分辨率、高灵敏度望远镜的存在，现在有大量关于活动星系核（AGN）以及黑洞X射线双星等星系源的相对论性喷流的观测数据。由于喷流速度不能很好地从观测中得到约束，但通常被认为是相对论性的，因此从观测中推断出的物理量通常用未知的光束参数来表示：体洛伦兹因子和视线角，通常以它们的组合作为相对论性多普勒因子。本文旨在解决文献中关于这种“去聚束”的导出量，特别是关于最小能量磁场估计存在的差异。出现这种差异是因为通常不区分用不同的波束参数观测到的固定源的情况和源在天空上的投影保持固定的情况。前者通常被认为是，但它是后者，对应于解释实际射流观测。此外，我们注意到，视超光速运动有一个空间推论，这里称为“延迟放大”，这意味着实际上存在于观测者坐标系（相对论术语中的“世界地图”）中的相对论性喷流的大部分实际上隐藏在观测者的图像上（一般的“世界图像”，或天文学特殊情况下的“超快照”）。
英文摘要：
Thanks to the availability of high-resolution high-sensitivity telescopes such as the Very Large Array, the Hubble Space Telescope, and the Chandra X-ray Observatory, there is now a wealth of observational data on relativistic jets from active galactic nuclei (AGN) as well as galactic sources such as Black-Hole X-ray Binaries. Since the jet speeds cannot be constrained well from observations, but are generally believed to be relativistic, physical quantities inferred from observables are commonly expressed in terms of the unknown beaming parameters: the bulk Lorentz factor and the line-of-sight angle, usually in their combination as relativistic Doppler factor. This paper aims to resolve the discrepancies existing in the literature about such "de-beaming" of derived quantities, in particular regarding the minimum-energy magnetic field estimate. The discrepancies arise because the distinction is not normally made between the case of a fixed source observed with different beaming parameters and the case where the source projection on the sky is held fixed. The former is usually considered, but it is the latter that corresponds to interpreting actual jet observations. Furthermore, attention is drawn to the fact that apparent superluminal motion has a spatial corollary, here called "retardation magnification", which implies that most parts of a relativistic jet that are actually present in the observer's frame (a "world map" in relativity terminology) are in fact hidden on the observer's image (the "world picture" in general, or "supersnapshot" in the special case of astronomy).
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
