Active Galaxies and Quasars the most luminous objects in 活动星系和类星体的最明亮的物体

Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,Black holes:do they exist?,Plan of talk,What are black holes?,Why should they exist?,How do we detect them?,The evidence:,binary star systems;,normal galaxies;,active galaxies and quasars.,Conclusions,Endpoints of stellar evolution,-Low mass star,(M Planetary Nebula,+,White Dwarf,(M 8M,sun,),-Supernova,+,Neutron Star,(M 2.5M,sun,),Normal Galaxies,Spiral Galaxy,Elliptical Galaxy,(Hubble 1924),X-ray binary system,Spectroscopic Binaries,Black Holes in X-ray Binary Systems,Measurements of the secondary stars in some X-ray binaries indicate primary star masses 2.5xMsun(above the mass limit for a neutron star),Corrected for inclination,the primary star masses are 10 xMsun,The primary stars are“dark in the sense that they make no contribution to the spectrum of the system.,-X-ray binaries provide excellent evidence for black holes,Seyfert Galaxies,Seyfert(1943),Optical images,Optical spectra,The discovery of the quasar 3C273,Optical image,Optical spectrum,At the distances estimated from the redshifts of the,emission lines,quasars have a luminosity 10-10,000 x the,integrated light of all the stars in the Milky Way.,(Schmidt 1963),z=0.158,Active nuclei:key characteristics,Large luminosities,(1-10,000 galaxies),Small size of emitting region,(Good evidence for super-massive black holes in most massive galaxies,The masses of the black holes correlate with the masses of the bulges of the host galaxies,Correlation between black hole mass and galaxy bulge mass/luminosity,Kormendy&Richstone(1995),The discovery of the quasar 3C273,Optical image,Optical spectrum,At the distances estimated from the redshifts of the,emission lines,quasars have a luminosity 10-10,000 x the,integrated light of all the stars in the Milky way.,(Schmidt 1963),z=0.158,Cygnus A viewed by HST,The quasar,nucleus in,Cygnus A,HST/NICMOS infrared 2.2,m,m image,Optical images,2.0 micron image,HST/NICMOS,Evidence for a super-massive black hole in Cygnus A from,Keck/NIRSPEC infrared data,Tadhunter et al.(2003),Evidence for a supermassive,black hole in Cygnus A from,HST/STIS data,M,bh,=(2.5+/-0.5)x10,9,M,sun,Tadhunter et al.(2003),Correlation between black hole mass and galaxy bulge mass/luminosity,Cygnus A,Galaxy Mergers,Conclusions,There is now compelling evidence(but not conclusive proof!)for super-massive black holes in:,-X-ray binary systems,-Normal galaxy cores,-Active galaxies and quasars,The black hole properties are strongly correlated with the properties of the bulges of the host galaxies.,The degree of nuclear activity is likely to depend on the amount of material being accreted(e.g.through galaxy mergers),