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TESTING THE PROPAGATING FLUCTUATIONS MODEL WITH A LONG, GLOBAL ACCRETION DISK SIMULATION
被引:56
作者:
Hogg, J. Drew
[1
,2
]
Reynolds, Christopher S.
[1
,2
]
机构:
[1] Univ Maryland, Dept Astron, College Pk, MD 20742 USA
[2] Univ Maryland, Joint Space Sci Inst JSI, College Pk, MD 20742 USA
关键词:
accretion;
accretion disks;
black hole physics;
magnetohydrodynamics (MHD);
BLACK-HOLE ACCRETION;
X-RAY BINARIES;
3-DIMENSIONAL MAGNETOHYDRODYNAMIC SIMULATIONS;
ANGULAR-MOMENTUM TRANSPORT;
SUPER-EDDINGTON ACCRETION;
WEAKLY MAGNETIZED DISKS;
LOCAL SHEAR INSTABILITY;
2 SPACE DIMENSIONS;
RMS-FLUX RELATION;
MAGNETOROTATIONAL INSTABILITY;
D O I:
10.3847/0004-637X/826/1/40
中图分类号:
P1 [天文学];
学科分类号:
0704 ;
摘要:
The broadband variability of many accreting systems displays characteristic structures; log-normal flux distributions, root-mean square (rms)-flux relations, and long inter-band lags. These characteristics are usually interpreted as inward propagating fluctuations of the mass accretion rate in an accretion disk driven by stochasticity of the angular momentum transport mechanism. We present the first analysis of propagating fluctuations in a long-duration, high-resolution, global three-dimensional magnetohydrodynamic (MHD) simulation of a geometrically thin (h/r approximate to 0.1) accretion disk around a black hole. While the dynamical-timescale turbulent fluctuations in the Maxwell stresses are too rapid to drive radially coherent fluctuations in the accretion rate, we find that the low-frequency quasi-periodic dynamo action introduces low-frequency fluctuations in the Maxwell stresses, which then drive the propagating fluctuations. Examining both the mass accretion rate and emission proxies, we recover log-normality, linear rms-flux relations, and radial coherence that would produce inter-band lags. Hence, we successfully relate and connect the phenomenology of propagating fluctuations to modern MHD accretion disk theory.
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页数:20
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