A constraint to black hole(BH)accretion has previously been derived for the inner edge fixed at the innermost stable circular orbit(ISCO)and the innermost bound circular orbit(IBCO).This constraint is referred to as t...A constraint to black hole(BH)accretion has previously been derived for the inner edge fixed at the innermost stable circular orbit(ISCO)and the innermost bound circular orbit(IBCO).This constraint is referred to as the mass-radius(MR)relation in this study,and the validity of the MR relation is discussed for different cases.It is shown that the product of the BH mass and the inner edge radius decreases monotonically in the accretion process for the inner edge located between IBCO and ISCO.In addition,we discuss the validity of the MR relation by considering the magnetic coupling(MC)effects of a Kerr BH with its surrounding disc.Although theoretically the product of the BH mass and the radius of ISCO increases(decreases)with time for a BH spin greater(less)than some critical value in the MC process,this relation is approximately valid for an Eddington accretion rate persisting for a rather long time,such as more than 10^(6)years.Finally,we discuss the possible application of the MR relation to astrophysics.展开更多
基金Supported by National Natural Science Foundation of China under Grant No 10873005the Research Fund for the Doctoral Program of Higher Education under Grant No 200804870050the National Basic Research Program of China under Grant No 2009CB824800.
文摘A constraint to black hole(BH)accretion has previously been derived for the inner edge fixed at the innermost stable circular orbit(ISCO)and the innermost bound circular orbit(IBCO).This constraint is referred to as the mass-radius(MR)relation in this study,and the validity of the MR relation is discussed for different cases.It is shown that the product of the BH mass and the inner edge radius decreases monotonically in the accretion process for the inner edge located between IBCO and ISCO.In addition,we discuss the validity of the MR relation by considering the magnetic coupling(MC)effects of a Kerr BH with its surrounding disc.Although theoretically the product of the BH mass and the radius of ISCO increases(decreases)with time for a BH spin greater(less)than some critical value in the MC process,this relation is approximately valid for an Eddington accretion rate persisting for a rather long time,such as more than 10^(6)years.Finally,we discuss the possible application of the MR relation to astrophysics.
