期刊
ASTROPHYSICAL JOURNAL
卷 762, 期 2, 页码 -出版社
IOP PUBLISHING LTD
DOI: 10.1088/0004-637X/762/2/68
关键词
accretion, accretion disks; black hole physics; galaxies: active; galaxies: jets
资金
- NASA [ATP NNX10AC84G]
- SAO [TM1-12007X]
- Marie Curie Career Integration grant [PCIG10-GA-2011-303609]
Massive black holes (BHs) in galactic nuclei vary their mass M-BH and spin vector J(BH) due to accretion. In this study we relax, for the first time, the assumption that accretion can be either chaotic, i.e., when the accretion episodes are randomly and isotropically oriented, or coherent, i.e., when they occur all in a preferred plane. Instead, we consider different degrees of anisotropy in the fueling, never confining to accretion events on a fixed direction. We follow the BH growth evolving contemporarily with mass, spin modulus a, and spin direction. We discover the occurrence of two regimes. An early phase (M-BH less than or similar to 10(7) M-circle dot) in which rapid alignment of the BH spin direction to the disk angular momentum in each single episode leads to erratic changes in the BH spin orientation and at the same time to large spins (a similar to 0.8). A second phase starts when the BH mass increases above greater than or similar to 10(7) M-circle dot and the accretion disks carry less mass and angular momentum relative to the hole. In the absence of a preferential direction, the BHs tend to spin-down in this phase. However, when a modest degree of anisotropy in the fueling process (still far from being coherent) is present, the BH spin can increase up to a similar to 1 for very massive black holes (M-BH >= 10(8) M-circle dot), and its direction is stable over the many accretion cycles. We discuss the implications of our results in the realm of the observations of BH spin and jet orientations.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据