Binary Black Hole Accretion Flows From a Misaligned Circumbinary Disk

摘要

Westudiedthebasicpropertiesofaccretionflowsontobinarysupermassiveblackholes,includingcasesinwhichacircumbinarydiskismisalignedwiththebinaryorbitalplane,bymeansofthree-dimensionalsmoothedparticlehydrodynamicssimulations.Wefindthatacircularbinarysystemwithamisalignedcircumbinarydisknormallyproducesadouble-peakedmass-accretion-ratevariationperbinaryorbit.Thisisbecauseeachblackholepassesacrossthecircumbinarydiskplaneandcapturesgastwiceinoneorbitalperiod.Eveninmisalignedsystems,however,asinglepeakedmass-accretion-ratevariationperbinaryorbitisproduced,iftheorbitaleccentricityismoderatelylarge($$egtrsim$$0.3).Thenumberofpeaksinthemassaccretionratescanbeunderstoodsimplyintermsoftheorbitalphasedependenceofthedistancebetweeneachbinaryblackholeanditsclosestinneredgeofthecircumbinarydisk.Inthecasesofeccentricbinaryblackholeshavingdifferentmasses,thelessmassiveblackholecangetclosertothecircumbinarydiskthanthemassiveone,thustidallysplittinggasfromitsinneredge,butthecreatedgasflowsarecomparablycapturedbybothblackholeswithashorttimedelay.Asaconsequence,thecombinedlightcurveshowsperiodicoccurrenceofdouble-peakedflareswithashortinterval.ThismayaccountfortheobservedlightvariationsofOJ287.