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Black Hole Mass of Active Galactic Nuclei

This research delves into methods for estimating black hole masses in active galactic nuclei (AGNs) using various dynamics and indirect techniques. It covers stellar dynamics, gas dynamics, water maser dynamics, and central engines of AGNs. The study discusses indirect methods such as fitting accretion disks, reverberation mapping, and BLR scaling with luminosity. It also explores the relationships between supermassive black holes (SMBH) and galactic bulges, BH mass estimations, and double-peaked broad emission line AGNs.

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Black Hole Mass of Active Galactic Nuclei

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  1. Black Hole Mass ofActive Galactic Nuclei Xue-Bing Wu (吴学兵) (Dept. of Astronomy, Peking Univ.) wuxb@bac.pku.edu.cn

  2. 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

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

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

  5. Water Maser Dynamics • Radio masers • 22 GHz microwave emission from extragalactic water masers • VLBA: resolution 0.0006as NGC 4258 M*=4E7 Msun Miyoshi et al. (1995)

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

  7. 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 yields 3 109 Msun. • Megamasers in edge-on nuclear gas disks: Sy2 NGC4258, 0.02 pc resolution gives perfect Keplerian rotation (pt mass), 3.6 107 Msun.

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

  9. Accretion disk fitting of the big blue bump in the spectra of AGN: evidence for AD (Sun & Malkan 1989) NGC 5548 AD model fits suggest 108-9.5 Msun for quasar, 107.5-8.5 Msun for Sy1s, plus mass accretion rates 0.1-1 and 0.01-0.5 times Eddington

  10. Reverberation mappingfrom optical variability Peterson (1997) • Broad emission line region: 0.01 - 1pc; Illuminated by the AGN's photoionizing continuum radiation and reprocess it into emission lines • RBLR estimated by the time delay that corresponds to the light travel time between the continuum source and the line-emitting gas: RBLR =c  t • V estimatedby the FWHM of broad emission line

  11. r  L0.6±0.1 r L1/2  QSOs (Kaspi et al. 2000)  Seyfert 1s (Wandel, Peterson, Malkan 1999)  Narrow-line AGNs  NGC 4051 (NLS1) BLR Scaling with Luminosity • To first order, AGN • spectra look the same • Same ionization parameter • Same density With the R-L relation, one can estimate the BLR size from the optical continuum luminosity

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

  13. 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) • 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 0.001 to 0.1) of 135 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

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

  15. AGN BH Mass estimation with the R-LH relation (Wu, Wang, Kong, Liu & Han 2004, A&A, 424, 793) • BLR sizes are usually derived previously from the empirical relation R L5100A0.7(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)

  16. 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-L5100A relation can overestimate MBH for radio-loud quasars • It may be better to use the relation between the emission line luminosity and the BLR size

  17. 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) • 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 (Bettoni et al. 2001)

  18. Summary and Discussion • Supermassive black holes with mass of 106 to 109 solar masses exist in the center of both normal and active galaxies • 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, MBH - relation and two R-L relations. • Estimating the BH mass is important and helpful to other studies on AGN and galaxy evolution

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

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

  21. Variations of broad line component at different luminosity level L Broad line component of CIV line of NGC 4151 Kong, Wu, Wang, Liu & Han (2006, A&A, 456, 473)

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

  23. BH fundamental plane from a uniform sample of radio and X-ray emitting broad line AGNs Wang, Wu & Kong (2006, ApJ, 645, 890) • Cross-identified RASS-SDSS-FIRST broad line AGNs • Different slope between the radio-quiet and radio-loud AGNs • Beaming effect from the relativistic jet of RL AGNs can affect the BH fundamental plane relation

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

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

  26. BH Masses of Distant Quasars Vestergaard 2004 How SMBHs form and grow?

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