Harvey Adam Leah W, Georganopoulos Markos, Meyer Eileen T
Department of Physics, University of Maryland, Baltimore County, 1000 Hilltop Circle, Baltimore, MD, 21250, USA.
NASA Goddard Space Flight Center, 8800 Greenbelt Rd, Greenbelt, MD, 20771, USA.
Nat Commun. 2020 Oct 30;11(1):5475. doi: 10.1038/s41467-020-19296-6.
Accretion onto the supermassive black hole in some active galactic nuclei (AGN) drives relativistic jets of plasma, which dissipate a significant fraction of their kinetic energy into gamma-ray radiation. The location of energy dissipation in powerful extragalactic jets is currently unknown, with implications for particle acceleration, jet formation, jet collimation, and energy dissipation. Previous studies have been unable to constrain the location between possibilities ranging from the sub-parsec-scale broad-line region to the parsec-scale molecular torus, and beyond. Here we show using a simple diagnostic that the more distant molecular torus is the dominant location for powerful jets. This diagnostic, called the seed factor, is dependent only on observable quantities, and is unique to the seed photon population at the location of gamma-ray emission. Using 62 multiwavelength, quasi-simultaneous spectral energy distributions of gamma-ray quasars, we find a seed factor distribution which peaks at a value corresponding to the molecular torus, demonstrating that energy dissipation occurs ~1 parsec from the black hole (or ~10 Schwarzchild radii for a 10M black hole).
在一些活动星系核（AGN）中，超大质量黑洞的吸积驱动了相对论性等离子体喷流，这些喷流将其相当一部分动能耗散为伽马射线辐射。强大的河外喷流中能量耗散的位置目前尚不清楚，这对粒子加速、喷流形成、喷流准直和能量耗散都有影响。先前的研究无法将位置限制在从亚秒差距尺度的宽线区域到秒差距尺度的分子环面及更远范围的各种可能性之间。在这里，我们通过一个简单的诊断方法表明，距离更远的分子环面是强大喷流的主要能量耗散位置。这个被称为种子因子的诊断方法仅取决于可观测的量，并且对于伽马射线发射位置的种子光子群体来说是独一无二的。利用62个伽马射线类星体的多波长、准同时光谱能量分布，我们发现种子因子分布在对应于分子环面的值处达到峰值，这表明能量耗散发生在距离黑洞约1秒差距处（对于一个10M的黑洞，约为10个史瓦西半径）。
