15 pages, 5 figures, accepted for publication in MNRAS. Corrected errors in jet efficiency formula in text and some equations in Appendices. Errors affected text only, results are unchanged
Unbounded outflows in the form of highly collimated jets and broad winds appear to be a ubiquitous feature of accreting black hole systems. The most powerful jets are thought to derive a significant fraction, if not the majority, of their power from the rotational energy of the black hole. Whatever the precise mechanism that causes them, these jets must therefore exert a braking torque on the black hole. We calculate the spin-up function for an accreting black hole, accounting for this braking torque. We find that the predicted black hole spin-up function depends only on the black hole spin and dimensionless parameters describing the accretion flow. Using recent relativistic magnetohydrodynamical numerical simulation results to calibrate the efficiency of angular momentum transfer in the flow, we find that an ADAF flow will spin a black hole up (or down) to an equilibrium value of about 96% of the maximal spin value in the absence of jets. Combining our ADAF system with a simple model for jet power, we demonstrate that an equilibrium is reached at approximately 93% of the maximal spin value, as found in the numerical simulation studies of the spin-up of accreting black holes, at which point the spin-up of the hole by accreted material is balanced by the braking torque arising from jet production. Our model also yields a relationship between jet efficiency and black hole spin that is in surprisingly good agreement with that seen in the simulation studies, indicating that our simple model is a useful and convenient description of ADAF inflow - jet outflow about a spinning black hole for incorporation in models of the formation and evolution of galaxies, groups and clusters of galaxies.
Racah Institute of Physics, The Hebrew University of Jerusalem（拉卡物理研究所，耶路撒冷希伯来大学）；Department of Physics and Astronomy, Johns Hopkins University（约翰斯·霍普金斯大学物理与天文学系）
Surfatron acceleration of the high energy protons in the relativistic jets
本文描述了在相对论性喷流的不稳定区中产生的喷流框架中，静电波捕获的高能质子的加速，在该区域中激发出螺旋结构。该波具有$\exp(i k_\parallel z +i m_ϕϕ)$的空间非均匀结构。质子可以在螺旋波产生的势阱中被捕获，从而通过一种称为表面加速器的机制经历加速。得到了射流参数的最大能量（$ E_p \simeq 10^{19} eV $）和能谱的表达式。
Particle acceleration at recollimation shocks in sub-relativistic jets. A model for jets in Seyfert Galaxies, Microquasars and Protostellar Systems
INAF, Istituto Nazionale di Astrofisica（意大利国家天体物理研究所）；Universite Paris Cité（巴黎西岱大学）；Université Côte d’Azur, Observatoire de la Côte d’Azur, CNRS, Laboratoire Lagrange（法国蔚蓝海岸大学，蔚蓝海岸天文台，法国国家科学研究中心，拉格朗日实验室）；University of Pisa（比萨大学）；Institute of Nuclear Physics Polish Academy of Sciences（波兰科学院核物理研究所）
