Convection-Dominated, Magnetized Accretion Flows into Black Holes

Publications of the Astronomical Society of Japan

Matsumoto, Ryoji¹  Mineshige, Shin²  Machida, Mami¹ 

[1] Department of Physics, Chiba University, 1-33 Yayoi-Cho, Inage-ku, Chiba 263-8522;;Department of Astronomy, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502

关键词: "accretion;    accretion disks";    "black holes";    convection;    "magnetohydrodynamics (MHD)";    outflow;   

DOI  :  10.1093/pasj/53.1.L1

学科分类：天文学(综合)

来源: Oxford University Press

【 摘 要 】

Two-dimensional(2D)andthree-dimensional(3D)hydrodynamicalsimulationshavebeenintensivelyperformedrecentlytoclarifytheaccretion-flowstructureinthelow-radiation-efficiencylimit.However,theresultsdependcriticallyontheparameterizedmagnitudeoftheviscosity,which,inprinciple,shouldbedeterminedself-consistentlybyMHDsimulations.Weanalyzedthestructureof3DMHDaccretionflowsinitiallythreadedbyweaktoroidalmagneticfields,andfoundforthefirsttimelarge-scaleconvectivemotionsdominatingneartotheblackhole.Radialprofilesofeachphysicalquantityinclude:thedensity,$$hoproptor^{-0.5}$$;radialvelocity,$$v_rproptor^{-1.5}$$;temperature,$$Tproptor^{-1.0}$$;andfieldstrength,$$B^2proptor^{-1.5}$$.Althoughtheflowstructure,itself,appearstobesimilartothoseobtainedbyhydrodynamicsimulations,theobservationalappearanceisdistinct.Unlikenon-magneticmodels,inwhichradiationisdominantattheoutermostconvectivezonesbecauseofoutwardenergyflowbyconvection,substantialaccretionenergycanbereleasedinthevicinityofablackholeinMHDflowviamagneticreconnection.Suchreconnectionleadstosporadicflareevents,thusproducingvariabilityinout-goingradiation,asiscommonlyobservedinobjectswithblack-holeaccretion.

【 授权许可】

Unknown