活动星系核统一模型和.ppt

Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,*,活动星系核统一模型和超大质量黑洞的形成与增长,张双南,清华大学物理系和,天体物理,中心,科学院高能所粒子天体物理重点实验室,Emission Line Spectra from,Seyfert,AGNs,Broad emission lines from Type-I,Seyfert,AGN,Narrow emission lines from Type-II,Seyfert,AGN,2,Unification scheme for type-I and type-II AGNs,3,Investigation of the obscuring,circumnuclear,torus in the active galaxy Mrk231:,Kloeckner,et al.,Nature,2003,The inferred model of the nuclear torus.The molecular material moves from top right to bottom left(northwest to southeast).,Virial,estimates of the central mass concentration give(7.23.8)x10,7,solar masses.,4,Sky deep surveys of,Chandra,and,HST,show that the fraction of type II AGN is decreasing with the hard X-ray luminosity.,This indicates a breakdown of the strong unification model where the covering factor,H/,R,i,is independent of luminosity and redshift.,This has been taken as the evidence of evolution of torus geometry,Hasinger et al 2003,Similar correlation has,been found by,Steffen,et al.(2003).,Sazonov,&,Revnivtsev,(2004),Wang&Zhang(2004),in other samples of,AGNs,5,Anisotropy of X-ray emission from AGNs,In all previous studies,it has been assumed implicitly that,However,if the X-rays originate from the accretion disk surrounding the black hole,the observed,apparent,X-ray luminosity is related to its,intrinsic,luminosity by:,Then for a given X-ray luminosity,randomly oriented AGNs will have apparent luminosity distribution:,6,The inclination angle effect,Data from,Ueda et al.2003,Zhang,2005,ApJ,618,L79,7,The inclination angle effect on type-II AGN fraction,Zhang,2005,ApJ,618,L79,8,考虑相对论效应对流强的修正,9,考虑相对论效应对光度的修正,Better agreement than,non-relativistic model,10,考虑相对论效应对光度的修正,11,考虑相对论效应对能谱的修正,a=0.998,倾角,:5 40 85,:0.89 0.85 0.75 (0.01),Sy,2 spectra are harder than,Sy,1 spectra for Kerr BHs,12,Anisotropy of inverse Compton scattering in corona,Maraschi,&,Haardt,1997,=0,o,=60,o,D,isk,kT,=50,eV,Disk,kT,=100,eV,Higher inclination for,S,ofter spectrum!,13,A.Malizia,ApJ 2003 589 L17,14,Inclination angle dependence of 2-10 keV spectral index,Zdziarski,et al.2000,Anisotropy of inverse Compton,scattering in spherical corona,Relativistic effects,(Disk origin in 2-10 keV),Averaged,Sy,I index,Sy,II index,Malizia,et al.2003,15,Implications of this,TAXI,model,TAXI model:,T,orus of,A,ntonucci,with,X,-ray,I,nclination-angle effects,X-rays are produced primarily in accretion disk,but,not,in extended and near-spherical corona,Many similarities in X-ray,variabilities,between X-ray binaries and AGNs suggest disk origin,Several theoretical models suggest viable mechanisms for X-ray production from AGN disks,e.g.,magnetic reconnection(like in the Sun),magnetic turbulent,Comptonization,Lack of broad Fe-K-alpha emission lines,Accretion disk and the torus are co-aligned with each other,Consistent with the model of,Krolik,and,Begelman,(1988)in which the torus feeds the black hole.,Question to be answered:How does the torus form the accretion disk surrounding the black hole?,16,Important correlations of SMBH mass with properties of galactic bulge,Stellar dynamics,Maser disk dynamics,Ionized gas dynamics,Black holes grow together with their host bulges.,17,No SMBH in M33?Merritt,et al,2001,Science,The M33 galaxy,850,kpc,spiral(disk)galaxy,with nuclear star cluster,expected to host a BH,But no bulge,No sharp increase of either,V,or,towards the center of the galaxy,Mass of the BH:3,10,3,M,BH grow together,only,with their host bulges,not with their disks.,18,Unstable by design:,Siemiginowska,and Elvis,Nature,1999,Lower stable branch:viscous heating balanced by cooling(BB radiation),Higher stable branch:viscous heating balanced by cooling(thermal,Bremsstralung,radiation),Middle unstable branch:UV photons strongly absorbed by hydrogen(ionization),cooling inefficient.,Increate accretion rate,Increase UV absorption,Jumps between lower and higher branches,Positive slope:stable disk,Negative slope:unstable disk,19,20,Advantages of the instability model,Previous problem for quasars,High luminosity,high accretion rate,Fuel run out quickly,many dead quasars in nearby galaxies:not found,New understanding,High luminosity implies the quasar disks cannot be in the lower branch,Irradiation of the disk insufficient to keep it in the higher branch permanently,Active quasars are those in the higher branch temporarily,due to irradiation instability,21,An Accretion Model for the Growth of the Central BH Associated with Ionization Instability in Quasars:,Lu,Cheng,Zhang,ApJ,2003,AGNs produce strong radiation because the BH accretes material from the host galaxy:,A BH may acquire significant mass through accretion,The accretion disk may not deliver all its material to the BH,as inferred from outflows in the forms of jets and galactic winds:,The ejected material may form the bulge,So we proposed an accretion model for the coeval growth of BH and bulge.,22,Model Assumptions,Assume an initial seed BH and disk are present.,Assume accretion rate of the disk in the higher branch of the S-shape is near Eddington-limit,and is thus modeled by the optically thick and geometrically thin solution.,Assume a sufficient cold gas is supplied by the quasar host galaxy.,Assume the disk in the lower branch of S-shape is modeled by relativistic advection dominated inflow-outflow solution(ADIOS).,23,Basic equations,Lower branch:ADIOS model(Becker et al.2001),Higher branch:Keplerian model(Pringle 1981;,Smak,1984),0.0250.1,24,The accreted matter(,M,bh,),acc,is about 10,-3,of the total,outflowing,mass,M,out,.,Based on model parameters for the accretion rates in,different branches:a seed BH with mass 2,10,6,M,can grow up to BH with mass 2,10,8,M,within 10,Gyr,.,Radiation efficiency in the lower branch:,0.025 10,6,M,)produced in the early Universe?,Some extremely massive BHs(10,9,M,)are found at very high redshift.,26,SMBH formation in the early Universe:,Shen,Hu,Lou&Zhang,submitted to ApJ,First generation stars 100,M,(made of primordial material,almost entirely H and He)formed at z30,but evolved quickly into supernova and left 10-100,M,BHs,A two-phase accretion model of SMBH formation:,a rapid accretion mainly of self-interacting dark matter(SIDM)onto 10-100,M,BHs to form,M,BH,10,6,M,at very high redshift(,z,15-20),a subsequent growth via normal baryonic accretion at the Eddington limit to,M,BH,10,9,M,before redshift,z,6.,27,Self-Interacting Dark Matter(SIDM)Accretion,Simulations of structure formation in the Universe prefer SIDM model(angular momentum)with specific cross section:,The first large-scale structures formed are dark matter halo.Assuming isothermal density profile,Then the BH mass growth:,28,Baryonic Eddington Accretion Phase,Exponential growth of BH mass via baryonic Eddington accretion:,Salpeter,(1964),To make 10,9,M,from 10,6,M,it takes 510,8,years,i.e.,just a few percent of the age of the Universe,However such SMBHs in the early Universe are very rare most quasars are not accreting at Eddington rate,continuouslyour,S-curve instability BH growth model,Persistent BH binaries are also very rare;most BH binaries are transients(the same S-curve).,Coincident?,29,Summary,Unification model of Active Galactic Nuclei,BH+Accretion Disk+Dusty Torus;Disk and Torus are coplanar,Most EM-radiation from disk and the torus covers part of the disk,Observed disk flux is inclination angle dependent:Type I AGNs are normally brighter than Type II AGNs,Two models coeval growth of supermassive BH with bulge,Mergers of smaller systems,Accretion of material from the disk(BH growth)and outflows from the disk(bulge growth),Formation of seed supermassive BHs,Bondi,(spherical)accretion of self-interacting dark matter halo,Growth of some supermassive BHs(in a small percentage of quasars)in the early Universe,Eddington accretion of baryonic matter onto seed supermassive BHs.,30,Further work and open questions,Is X-ray emission from AGNs really from accretion disk?,Previously the X-ray emission is usually believed from optically thin corona.,If the X-ray emission is really from the disk,then relativistic effects on its continuum spectra should be revealed.,Maybe for individual AGN we can find a way to estimate its inclination angle accurately and then study the spectral correlation with the inclination angle?,For our two phase BH growth model,one important question to ask is:can this model reproduce the observed luminosity function of AGNs?,Which kind of accretion history is required to produce the LF?,How much dark matter is turned into 10,6,M,in the early Universe?Is there any way to detect these BHs?,31,