Magnetic reconnection: flares and coronal heating in active galactic nuclei

被引:115
作者
Di Matteo, T [1 ]
机构
[1] Univ Cambridge, Inst Astron, Cambridge CB3 0HA, England
关键词
accretion; accretion discs; magnetic fields; MHD; galaxies : active;
D O I
10.1046/j.1365-8711.1998.01950.x
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
A magnetically structured accretion disc corona, generated by buoyancy instability in the disc, can account for observations of flare-like events in active galactic nuclei. We examine how Petschek magnetic reconnection, associated with MHD turbulence, can result in a violent release of energy and heat the magnetically closed regions of the corona up to canonical X-ray emitting temperatures. X-ray magnetic flares, the after effect of the energy released in slow shocks, can account for the bulk of the X-ray luminosity from Seyfert galaxies and consistently explain the observed short-time-scale variability.
引用
收藏
页码:L15 / L20
页数:6
相关论文
共 20 条
[1]   A POWERFUL LOCAL SHEAR INSTABILITY IN WEAKLY MAGNETIZED DISKS .1. LINEAR-ANALYSIS [J].
BALBUS, SA ;
HAWLEY, JF .
ASTROPHYSICAL JOURNAL, 1991, 376 (01) :214-222
[2]   MAGNETIC-FIELD RECONNECTION IN A COLLISIONLESS PLASMA [J].
CORONITI, FV ;
EVIATAR, A .
ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES, 1977, 33 (02) :189-210
[3]   Two-temperature coronae in active galactic nuclei [J].
DiMatteo, T ;
Blackman, EG ;
Fabian, AC .
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 1997, 291 (01) :L23-L27
[4]  
DIMATTEO T, 1998, UNPUB MNRAS
[5]   STRUCTURED CORONAE OF ACCRETION DISKS [J].
GALEEV, AA ;
ROSNER, R ;
VAIANA, GS .
ASTROPHYSICAL JOURNAL, 1979, 229 (01) :318-326
[6]   X-RAY-SPECTRA FROM 2-PHASE ACCRETION DISKS [J].
HAARDT, F ;
MARASCHI, L .
ASTROPHYSICAL JOURNAL, 1993, 413 (02) :507-517
[7]  
HAARDT F, 1994, APJ, V432, pL92
[8]   Magnetohydrodynamic turbulence and implications for solar coronal heating [J].
Hendrix, DL ;
VanHoven, G .
ASTROPHYSICAL JOURNAL, 1996, 467 (02) :887-893
[9]   EMERGING FLUX MODEL FOR SOLAR-FLARE PHENOMENON [J].
HEYVAERTS, J ;
PRIEST, ER ;
RUST, DM .
ASTROPHYSICAL JOURNAL, 1977, 216 (01) :123-137
[10]   ENERGY FLUX LIMITATION BY ION-ACOUSTIC TURBULENCE IN LASER FUSION SCHEMES [J].
MANHEIMER, WM .
PHYSICS OF FLUIDS, 1977, 20 (02) :265-270