天体物理概论活动星系核.ppt

problem：ToofewType2QSOs!Type1AGNSEDManners,2002mmfar-IRnear-IROptical-UVX-raysType2AGNSEDNormanetal,2002Radiofar-IRoptical-UVX-rayssynchrotrondustcoldaccretiondiskthermalComptonHotcoronaThermalComptonComptoninverseThermalemissionSED与辐射机制Jets:SomeAGNshownarrow“jets”ofmaterialejectedfromthenucleus,emittingatradio,optical,andX-raywavelengths.Jetssometimesmoveatclosetothespeedoflight.Theypresumablyoriginateintheinnerpartoftheaccretiondisk,possiblypropelledbyelectromagneticforces.(astro-ph/0611605)Radiosources:Compactradiosourcesarelocatedinthegalacticnucleus,withdimensionsofparsecstokiloparsecs.Extendedradiosourcestypicallyinvolvetwolargevolumes(“lobes”)ofemittingmaterialonoppositesidesofthehostgalaxyatdistancesofhundredsofkpc.Jetscarryingenergyfromthenucleustothelobesaresometimesobserved.JetandRadiosourcesJets:focussedstreamsofionizedgasenergycarriedoutalongchannelslobehotspotmaterialflowsbacktowardsgalaxyjethttp://www.mssl.ucl.ac.uk/Junoretal.,Nature,28October1999RadiojetofM87(FRIradiogalaxy)X-rayandopticalJetBook,fig8.5它们是不是同一个起源？辐射机制射电、光学、X-rayAstro-ph/0605530(3C273)M87*ItiscommonlyacceptedthatAGNareallmanifestationsofaccretionontoasupermassiveblackhole.Thisisdeducedfrom:1.Theveryhighluminositiesinvolved,upto~1e47erg/sormore2.FastvariabilityontimescalesofonlydaysorevenshorterforBLLacsandoptically-violentvariables.Thefastvariabilityimpliesaverysmallsourcesizeforthenucleus.Ifthetimetakentovarysignificantlyis10,000seconds(forexample),thenthesizeofthesourcemustbenomorethan1e4timesthespeedoflight,whichis3e12m.ThiscorrespondstotheSchwarzchildradiusofa1e9solarmassblackhole.**Jetsappeartobechannelsalongwhichenergyiscarriedouttothelargescalelobesa