Supermassive Black Holes in Galactic Nuclei Xue-Bing Wu ( 吴学兵 ) (Dept. of Astronomy, Peking Univ.)

Content 1 Black holes in the universe 2 Supermassive black holes in active galactic nuclei 3 Recent progress in AGN BH mass study 4 Summary & discussion

Brief history of ‘ black hole ’ concept 'Black hole' in classical physics 'Black hole' in classical physics –‘ Dark star ’ was suggested in 1783 by John Mitchell. –It was rejected soon in 1808 because of Thomas Young ’ s light interference experiment. 'Black hole' in modern physics 'Black hole' in modern physics –General relativity predicted it: Schwarzschild ’ s ‘ singularity ’. –Einstein rejected it for philosophical reasons. –Chandrasekhar ’ s white dwarf mass limit demanded it. –Eddington rejected it, again for philosophical reasons. –Oppenheimer ’ s neutron star mass upper limit demanded it. –Wheeler rejected it, and again for philosophical reasons. –Wheeler was finally convinced of it and named it ‘ BLACK HOLE ’ in –Black hole physics finally got off-ground since then.

1. BHs in the universe Three categories of astrophysical BHs Three categories of astrophysical BHs –Primordial BHs: M~10^15g, not detected yet –Stellar-mass BHs: M~3-20 solar masses, ~20 detected in BH X-ray binaries –Supermassive BHs: M~10^6-10^9 solar masses, exist in the center of galaxies Intermediate-mass BHs: M~10^2-10^4 solar masses (??) Intermediate-mass BHs: M~10^2-10^4 solar masses (??)

Primordial Black Holes: Basic Properties Proposed by S. Hawking Proposed by S. Hawking Mass: grams Mass: grams –Lighter ones already died Radius: cm Radius: cm Density: grams/cm 3 Density: grams/cm 3 Temperature: K Temperature: K Lifetime: years Lifetime: years –Some are dying now Fate: evaporation leading to final explosion Fate: evaporation leading to final explosion –Strong gamma-ray emission –None observed yet!

An Example of Stellar-mass BH: Cyg X-1 Mass function: Cyg X-1

Supermassive Black Holes in Nearby Galaxies (Kormendy & Richstone 1995; Kormendy & Gebhardt 2001; Ho 1999) Stellar dynamics Mass determined by the rotational velocity V and the velocity dispersion  of stars Gas dynamics Keplerian rotation of ionized gas in a disk-like configuration Water maser dynamics 22 GHz microwave emission from extragalactic water masers

Stellar Dynamics NGC 3115 (Kormendy et al. 1996) M * =2E9 Msun 25 times massiver than the visible star cluster

Stellar Dynamics Our Galaxy (Genzel et al. 1997; 2003) M * =(3~4) E6 Msun Stellar velocity & proper motions around Sgr A* yield a BH mass of (3~4) 10 6 Msun

Gas Dynamics – –Optical emission lines M87: H, [NII] M * =2.4E9 Msun Macchetto et al. (1997)

Water Maser Dynamics – –Radio masers 22 GHz microwave emission from extragalactic water masers VLBA: resolution as NGC 4258 M * =4E7 Msun Miyoshi et al. (1995)

Determination of Supermassive black hole masses in the center of galaxies ( Kormendy & Gebhardt 2001)

2 Supermassive Black Holes in Active Galactic Nuclei (AGN)

What makes AGN interesting? Prodigious luminosity (~1E46erg/s) emitted in a tiny volume (<pc 3 ) over an extraordinary broad range of frequencies, displaying strong emission lines whose widths suggesting velocities ranging up to ~10000 km/s AGN Zoo Seyfert Galaxies; Quasars; Radio Galaxies Blazars (BL Lacs & OVVs); LINERs and ULIRGs

VariabilitiesSpectra

Examples of quasars identified by ourselves (Wu, Bade & Beckmann, 1999, A&A, 347, 63)

Central engine of AGNs Supermassive black hole Accretion disk Broad line region Dusty torus Narrow line region Jet

Black hole mass estimations of AGNs Direct methods Stellar dynamical studies not feasible in AGN, since the AGN outshines the stars. Can use gas kinematics, if the gas is seen in Keplerian rotation. In M87, r=75 pc disk (NOT Accretion Disk) yields Msun,  >10 7 Msun pc -3 Megamasers in edge-on nuclear gas disks: Sy2 NGC4258, 0.02 pc resolution gives perfect Keplerian rotation (pt mass), Msun,  > Msun pc -3 ; proper motions & radial accelerations also measured, allowing a distance determination to be made

Indirect Methods Accretion disks fitting of the big blue bump in the spectra of AGN – –Standard thin disk model (Shakura & Sunyaev 1973):

AD model fits suggest Msun for quasar, Msun for Sy1s, plus mass accretion rates and times Eddington NGC 5548 Accretion disk fitting of the big blue bump in the spectra of AGN: evidence for AD (Sun & Malkan 1989)

Broad gravitational-redshifted Iron K  line of Seyfert 1 galaxies--accretion disk modeling Tanaka et al. (1995); Nandra et al. (1997) Fabian et al. (1989)

– –Broad emission line region: pc; Illuminated by the AGN's photoionizing continuum radiation and reprocess it into emission lines – –R BLR estimated by the time delay that corresponds to the light travel time between the continuum source and the line-emitting gas: R BLR =c  t – –V estimated by the FWHM of broad emission line Reverberation mapping from optical variability Peterson (1997)

Determination of Supermassive black hole masses of AGN with reverberation mapping Kaspi et al. (2000)

BLR Scaling with Luminosity  QSOs (Kaspi et al. 2000)  Seyfert 1s (Wandel, Peterson, Malkan 1999)  Narrow-line AGNs  NGC 4051 (NLS1) r  L 0.6±0.1 To first order, AGN spectra look the same Þ Þ Same ionization parameter Þ Þ Same density r  L 1/2 With the R-L relation, one can estimate the BLR size from the optical continuum luminosity

SMBH and Galactic Bulge Relations of black hole mass with bulge luminosity and central velocity dispersion (for normal galaxies & AGNs) Ferrarese et al. (2001) AGN With the M-σ relation, one can estimate the BH mass from the stellar velocity dispersion

Primary Methods: Phenomenon:BL Lac Objects Quiescent Galaxies Type 2 AGNs Type 1 AGNs Methods of estimating SMBH Masses Stellar, gas dynamics Megamasers2-d RM 1-d RM Fundamental Empirical Relationships: M BH –  * AGN M BH –  * Secondary Mass Indicators: Fundamental plane:  e, r e   *  M BH Broad-line width V & size scaling with luminosity R  L 0.7  M BH Low-z AGNs High-z AGNs [O III ] line width V   *  M BH Peterson (2004)

3. Recent progress in AGN BH mass study 1. On black hole masses, radio loudness and bulge luminosities of Seyfert galaxies, Wu & Han 2001, A&A, 380, Inclinations and black hole masses of Seyfert 1 galaxies, Wu & Han 2001, ApJ, 561, L59 3. Supermassive black hole masses of AGNs with elliptical hosts, Wu, Liu, & Zhang 2002, A&A, 389, Black hole mass and binary model for BL Lac object OJ 287, Liu & Wu 2002, A&A, 388, L48 5. Black hole mass estimation with a relation between the BLR size and emission line luminosity of AGN, Wu, Wang, Kong, Liu, & Han 2004, A&A, 424, Black hole mass and accretion rate of AGNs with double-peaked broad emission line, Wu & Liu 2004, ApJ, 614, 91

(1) Estimation of BH masses of Seyfert galaxies (Wu & Han 2001, A&A, 380, 31) Sample of Seyfert galaxies Sample of Seyfert galaxies 37 Seyferts (22 Sy 1s, 15 Sy 2s) with measured M BH or  from two bright Seyfert samples –Palomar: B < 12.5 mag, 49 Seyferts (21 Sy 1s, 28 Sy 2s) 21 Sys selected (13 Sy 1s, 8 Sy2s) –CfA: Zwicky magnitude <14.5, 48 Sys (33 Sy 1s, 15 Sy 2s) 23 Sys selected (15 Sy 1s, 8 Sy2s), 8 common with Palomar sample –5 Sys with dynamical measured M BH, 10 Sy 1s with M BH measured by reverberation mapping –22 Sys with measured  but unknown M BH (M-σ relation applies here!)

Sample of Seyfert galaxies Sample of Seyfert galaxies

Relation of radio power with SMBH masses Relation of radio power with SMBH masses Correlation between BH mass and bulge magnitude M V bulge = log (M BH /M sun ) => M BH  M bulge 1.74 a non-linear relation ！

(2) Determing the BLR inclination of Seyfert 1 galaxies based on BH mass estimations (2) Determing the BLR inclination of Seyfert 1 galaxies based on BH mass estimations (Wu & Han 2001, ApJ, 561, L59) BLR dynamics (Wills & Browne 1986) BLR dynamics (Wills & Browne 1986) Virial BH mass Virial BH mass BH mass-velocity dispersion relation (Gebhardt et al. 2000) BH mass-velocity dispersion relation (Gebhardt et al. 2000)

Inclinations of BLR in Seyfert galaxies Mean value of 36 degree, supporting the AGN unification scheme!

Inclinations of BLR in Seyfert galaxies NLS1 Inclination affects the line width; NLS1s seem to have smaller BH masses.

(3) SMBH Mass of AGNs with elliptical host galaxy (Wu, Liu & Zhang, 2002, A&A, 389, 742) Reverberation mapping can not apply to BL Lacs; Only 10 BL Lacs have measured  values (Falomo et al. 2002; Barth et al. 2002)Reverberation mapping can not apply to BL Lacs; Only 10 BL Lacs have measured  values (Falomo et al. 2002; Barth et al. 2002) Host galaxies of BL Lacs are ellipticals (Urry et al. 2000)Host galaxies of BL Lacs are ellipticals (Urry et al. 2000)  values can be derived based on the fundamental plane of ellipticals; then SMBH masses could be estimated for BL Lacs with high-quality images  values can be derived based on the fundamental plane of ellipticals; then SMBH masses could be estimated for BL Lacs with high-quality images (Bettoni et al. 2001)

Comparison of Eddington ratios of AGNs Comparison of Eddington ratios of AGNs The Eddington ratios (dimensionless accretion rates) of radio galaxies are about two orders lower than those of quasars.

(4) Black hole mass and binary BH model for BL Lac object OJ 287 (Liu & Wu, A&A, 2001, 388, L48) OJ 287, one of the best studied BL Lacs with optically outbursts recurrent with a period of year (Sillanpaa et al. 1988). A predicted optical outburst in 1994 was observed and a binary black hole model is favored (Lehto & Valtonen 1996). The previous binary BH model requires the primary BH mass of 1.5E10 solar masses (Pietila 1999), which is much larger than the estimated BH masses of other BL Lac objects. A new binary BH model (Valtaoja et al. 2000) with BH mass <1E9 solar mass can explain the observed double-peaked outburst behavior.

msms  (Valtaoja et al. 2000)

Primary black hole mass of OJ 287: The host galaxy was marginally resolved of an effective radius r e =0.72’’ and R-band absolute magnitude M R = (Heidt et al. 1999) Using the BH mass – bulge luminosity relation (McLure & Dunlop 2002), It gives M BH =4.6E8 solar masses. M BH -  Using the fundamental plane and the M BH -  relation, It gives M BH =3.2E8 solar masses.  M BH ~4E8 solar masses  Support the new binary BH model (Valtaoja et al 2000)

(5) AGN BH Mass estimation with the R-L H  relation (Wu, Wang, Kong, Liu & Han 2004, A&A, 424, 793) BLR sizes are usually derived previously from the empirical relation R  L 5100A 0.7 (Kaspi et al. 2000). Can it apply to RL AGN? Optical jets of some AGNs have been observed by the HST (Scarpa et al. 1999; Jester 2003; Parma et al. 2003). Optical Synchrotron radiations have been found in some RL AGNs (Whiting et al. 2001; Chiaberge et al. 2002; Cheung et al. 2003)

For RL AGNs, optical continuum luminosity may be significantly contributed from jets, and may not be a good indicator of ionizing luminosity Using the R-L 5100A relation can overestimate M BH for radio-loud quasars It may be better to use the relation between the emission line luminosity and the BLR size

Recently we also extended such a study to UV broad emission lines (Mg II & CIV) (Kong, Wu, Wang, & Han, 2006)

(6) Black hole mass and accretion rate of AGNs with double-peaked broad emission line (Wu & Liu, 2004, ApJ, 614, 91) Double-peaked broad line AGNs are usually believed to be LINER-type low-luminosity ones (Ho et al. 2001) Double-peaked broad line AGNs are usually believed to be LINER-type low-luminosity ones (Ho et al. 2001) 150 double-peaked AGN discovered (SDSS and RLAGN); SDSS double-peaked AGNs: 76% are radio-quiet, with medium luminosities (1E44 erg/s); 12% are LINER (Strateva et al. 2003) 150 double-peaked AGN discovered (SDSS and RLAGN); SDSS double-peaked AGNs: 76% are radio-quiet, with medium luminosities (1E44 erg/s); 12% are LINER (Strateva et al. 2003) With the R-L relation, we estimated the BH mass (from 3E7 to 5E9 solar masses) and the Eddington ratio (from to 0.1) of 135 double-peaked AGNs. With the R-L relation, we estimated the BH mass (from 3E7 to 5E9 solar masses) and the Eddington ratio (from to 0.1) of 135 double-peaked AGNs. We found big blue bumps in some luminous double-peaked AGNs We found big blue bumps in some luminous double-peaked AGNs We suggested that for luminous double-peaked AGNs with Eddington ratio larger than 0.01, the accretion process is probably different from that of LINER-type double-peaked AGNs We suggested that for luminous double-peaked AGNs with Eddington ratio larger than 0.01, the accretion process is probably different from that of LINER-type double-peaked AGNs

Black hole mass and accretion rate of AGNs with double-peaked broad emission line

4. Summary and Discussion Supermassive black holes with mass of 10 6 to 10 9 solar masses exist in the center of both normal and active galaxies M BH -  Direct dynamic methods of estimating the BH mass can only be applied to several nearby AGNs. Reliable BH mass of AGNs can be obtained by reverberation mapping, M BH -  relation and two R-L relations. Estimating the BH mass is important and helpful to other studies on AGN and galaxy evolution

Eddington ratio and accretion physics in different types of AGN From the BH mass, we can derive Eddington ratio ( L bol /L edd ), which measures the accretion rate in Eddington unit. Accretion disk structure is strongly dependent on the accretion rate SD: Slim disk (Abramowicz et al. 1988) RTD, GTD: Radiation pressure and gas pressure dominated thin disk (Shakura-Sunyaev 1973) SLE: Hot, two-temperature disk (Shapiro, Lightman & Eardley 1976) ADAF: Advection dominated accretion flow (Narayan & Yi 1994) Abramowicz et al. (1995)

Transition of different accretion modes as accretion rate changes Applications in black hole X-ray binaries: (AGN too?) Fender (2003)

Knowing accretion rate may help us to understand the broad line region physics of AGN (Nicastro et al. 2003)

Variations of broad line component at different luminosity level Kong, Wu, Wang, Liu & Han (2006, A&A) Broad line component of CIV line of NGC 4151 L

“A fundamental plane of black hole activity” (Merloni et al. MNRAS, 2003) Common physics in BH systems(?): BH, accretion disk, jet…

BH fundamental plane from a uniform sample of radio and X-ray emitting broad line AGNs Cross-identified RASS-SDSS-FIRST broad line AGNs Different slope between radio-quiet and radio-loud AGNs Beaming effect from the relativistic jet of RL AGNs can contaminate the BH fundamental plane relation Wang, Wu & Kong (2006, ApJ)

Radio--X-ray correlation with different X-ray origins (Yuan & Cui 2005, ApJ) Consistent with the results obtained with our uniform sample! Flat slopeSteep slope

SMBH and Galaxy Formation Black hole formation is closely related to galaxy formation Tremaine et al. (2002) M BH  4

SMBH in highest redshift quasar (z=6.4) Willott et al. (2003) (UKIRT/UIST) FWHM(MgII)=6000km/s  M BH =3E9 Msun Barth et al. (2003) (Keck II/NIRSPEC) FWHM(MgII)=5500km/s  M BH =2E9 Msun FWHM(CIV)=9000km/s  M BH =6E9 Msun Supermassive black hole formed in the early universe!

Ree’s flow chart for the formation of a very massive black hole

How BHs grow to 10 9 solar masses before z=6? Accretion or merging? How BHs grow to 10 9 solar masses before z=6? Accretion or merging? –Hierarchical growth of BH by merging and gas accretion can produce such a SMBH, if the seed BH can form at z>10 (Haiman & Loeb 2001; Volonteri et al. 2003, 2005) –The initial seed BH (M~ Msun) may be formed by collapse of massive first generation stars in the early Universe (Madau & Rees 2001; Schneider et al. 2002) –A single BH (M~180Msun) at z=20 could also produce a SMBH with M= Msun if it were constantly accreting at the Eddington luminosity with a radiation efficiency of 0.1 (Barth et al. 2003).

How growing BHs regulate galaxy formation Black hole feedback: Black hole feedback: –When the galaxies and their black holes collide a quasar is ignited which expels most of the gas in a strong wind. The remaining galaxy contains very little gas but a large supermassive black hole. The black hole mass is related to the size of the galaxy in agreement with observations. (Di Matteo et al. 2005, Nature)

Future Efforts Detecting the gravitational wave produced by coalescing BHs with Laser Interferometer Space Antenna (LISA, 2010?)

Chinese Facilities in the Near Future LAMOST: LAMOST: The Large Sky Area Multi-Object Fiber Spectroscopic Telescope The optical spectroscopic survey carried out by LAMOST of tens of millions of galaxies and others will make substantial contribution to the study of extra-galactic astrophysics and cosmology, such as galaxies, quasars and the large-scale structure of the universe. The project will come into operation at the end of

Chinese Facilities in the Near Future FAST (Five hundred meter Aperture Spherical Telescope): The largest single dish radio telescope in the world HXMT (Hard X-ray Modulation Telescope)

Thank you Have fun with black holes !