The nuclei of most normal galaxies contain supermassive black holes, which can accrete gas through a disk and become active. These Active Galactic Nuclei, AGN, can form jets which are observed on scales from AU to Mpc and from meter wavelengths to TeV gamma ray energies. High resolution radio imaging and multi-wavelength/messenger campaigns are elucidating the conditions under which this happens. Evidence is presented that: AGN jets are formed when the black hole spins and the accretion disk is strongly magnetized, perhaps on account of gas accretingat high latitude beyond the black hole sphere of influence; AGN jets are collimated close to the black hole by magnetic stress associated with a disk wind; higher power jets can emerge from their galactic nuclei in a relativistic, supersonic and proton-dominated state and they terminate in strong, hot spot shocks; lower power jets are degraded to buoyant plumes and bubbles; jets may accelerate protons to EeV energies which contribute to the cosmic ray spectrum and which may initiate pair cascades that can efficiently radiate synchrotron gamma rays; jets were far more common when the universe was a few billion years old and black holes and massive galaxies were growing rapidly; jets can have a major influence on their environments, stimulating and limiting the growth of galaxies. The observational prospects for securing our understanding of AGN jets are bright.

中文翻译：

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来自活动星系核的相对论喷流

大多数正常星系的原子核都包含超大质量黑洞，它们可以通过圆盘吸积气体并变得活跃。这些活动星系核 AGN 可以形成射流，在从 AU 到 Mpc 以及从米波长到 TeV 伽马射线能量的尺度上观察到这些射流。高分辨率无线电成像和多波长/信使活动正在阐明发生这种情况的条件。有证据表明： AGN 喷流是在黑洞旋转和吸积盘被强磁化时形成的，这可能是由于在高纬度黑洞影响范围之外的气体吸积；AGN 喷流通过与盘风相关的磁应力在黑洞附近准直；更高功率的喷流可以以相对论、超音速和质子主导的状态从它们的星系核中出现，并以强、热点冲击；较低功率的喷流被降解为有浮力的羽流和气泡；喷流可以将质子加速到 EeV 能量，这对宇宙射线光谱有贡献，并且可以启动可以有效辐射同步加速器伽马射线的对级联；当宇宙有几十亿年的历史并且黑洞和大质量星系正在迅速增长时，喷流更为常见；喷流可以对其环境产生重大影响，刺激和限制星系的生长。确保我们了解 AGN 喷流的观测前景是光明的。当宇宙有几十亿年的历史并且黑洞和大质量星系正在迅速增长时，喷流更为常见；喷流可以对其环境产生重大影响，刺激和限制星系的生长。确保我们了解 AGN 喷流的观测前景是光明的。当宇宙有几十亿年的历史并且黑洞和大质量星系正在迅速增长时，喷流更为常见；喷流可以对其环境产生重大影响，刺激和限制星系的生长。确保我们了解 AGN 喷流的观测前景是光明的。