共 50 条
Magnetohydrodynamic simulations of a rotating massive star collapsing to a black hole
被引:62
作者:
Fujimoto, Shin-Ichirou
[1
]
Kotake, Kei
Yamada, Shoichi
Hashimoto, Masa-Aki
Sato, Katsuhiko
机构:
[1] Kumamoto Natl Coll Technol, Dept Elect Control, Kumamoto 8611102, Japan
[2] Waseda Univ, Adv Res Inst Sci & Engn, Shinjuku Ku, Tokyo 1698555, Japan
[3] Kyushu Univ, Sch Sci, Dept Phys, Fukuoka 8108560, Japan
[4] Univ Tokyo, Sch Sci, Dept Phys, Bunkyo Ku, Tokyo 1130033, Japan
[5] Univ Tokyo, Sch Sci, Res Ctr Early Universe, Bunkyo Ku, Tokyo 1130033, Japan
关键词:
accretion;
accretion disks;
gamma rays : bursts;
methods : numerical;
MHD;
supernovae : general;
D O I:
10.1086/503624
中图分类号:
P1 [天文学];
学科分类号:
0704 ;
摘要:
We perform two-dimensional, axisymmetric, magnetohydrodynamic simulations of the collapse of a rotating star of 40 M-circle dot in light of the collapsar model of gamma-ray bursts. Considering two distributions of angular momentum, up to similar to 10(17) cm(2) s(-1), and the uniform vertical magnetic field, we investigate the formation of an accretion disk around a black hole and the jet production near the black hole. After material reaches the black hole with high angular momentum, the disk forms inside a surface of weak shock. The disk reaches a quasi-steady state for stars whose magnetic field is less than 10(10) G before the collapse. We find that the jet can be driven by the magnetic fields even if the central core does not rotate as rapidly as previously assumed as long as the outer layers of the star have sufficiently high angular momentum. The magnetic fields are chiefly amplified inside the disk due to the compression and the wrapping of the field. The fields inside the disk propagate to the polar region along the inner boundary near the black hole through the Alfven wave and eventually drive the jet. The quasi-steady disk is not an advection-dominated disk but a neutrino cooling-dominated one. Mass accretion rates in the disks are greater than 0: 01 M-circle dot s(-1) with large fluctuations. The disk is transparent for neutrinos. The dense part of the disk, which is located near the black hole, emits neutrinos efficiently at a constant rate of < 8 x 10(51) ergs s(-1). The neutrino luminosity is much smaller than those from supernovae after the neutrino burst.
引用
收藏
页码:1040 / 1055
页数:16
相关论文