# Weighing black holes in radio-loud AGNs

## Presentation on theme: "Weighing black holes in radio-loud AGNs"— Presentation transcript:

Weighing black holes in radio-loud AGNs
Xue-Bing Wu (吳學兵) (Dept. of Astronomy, Peking Univ.) Collaborators: Ran Wang, F.K. Liu (PKU); M.Z. Kong, J.L. Han (NAOC)

Content Introduction BH mass from the BLR size - emission line luminosity relation BH mass from the fundamental plane relation of AGN elliptical hosts Summary

1. Introduction Most AGNs in Reverberation mapping studies are radio quiet. Can the R-L relation be applied to (extremely) radio-loud AGNs? For blazar-type AGNs, the emission line is weak/absent. How to estimate the BH mass of them?

BLR Scaling with Luminosity
R-L relation from photoionization model R-L relation from reverberation mapping r  L0.6±0.1 r  L1/2 (Kaspi et al. 2000, 2005) With the R-L relation, we 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) AGN Ferrarese et al. (2001) With the M-σ relation, we can estimate the BH mass from the stellar velocity dispersion

2. BH Mass from the R-LH relation
(Wu, Wang, Kong, Liu & Han 2004, A&A, 424, 793) BLR sizes are usually derived from an empirical relation R L5100A0.7(Kaspi et al. 2000, 2005). 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 It may be better to use the relation between the emission line luminosity and the BLR size

Using the R-L5100A relation one can overestimate MBH for extremely radio-loud quasars; using the R-LH relation may be more accurate.

Recently we also extend such a study to UV broad emission lines
(Mg II & CIV) (Kong, Wu, Wang, & Han, 2006, ChJAA, 6, 396)

BH mass of a blazar AO 0235+164 (Liu, Zhao & Wu, 2006, ApJ, 650, 749)
R-L5100A relation: 1.5 x 109 M R-LH relation: 5.8 x 108 M =FWHM[OII]/2.35 & M-σ relation: x 108 M The result from the R-L5100A relation is overestimated ->BH mass of AO : 4.7 x 108 M

3. BH Mass from the fundamental plane of AGN elliptical hosts
(Wu, Liu & Zhang, 2002, A&A, 389, 742) Reverberation mapping can not apply to BL Lacs; Only a dozen of 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 from the fundamental plane of ellipticals (Bettoni et al. 2001)

BH Mass from the fundamental plane of AGN elliptical hosts
SMBH masses could be estimated for BL Lacs and other AGNs with high-quality HST images

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

Primary black hole mass of OJ 287
(Liu & Wu, 2002, A&A, 388, L48) The host galaxy was marginally resolved of re=0.72’’ and R-band absolute magnitude MR= (Heidt et al. 1999) Using the BH mass – bulge luminosity relation (McLure & Dunlop 2002), It gives MBH=4.6E8 solar masses. Using the fundamental plane of elliptical hosts and the MBH -  relation, It gives MBH=3.2E8 solar masses.  MBH~4E8 solar masses  Support the new binary BH model (Valtaoja et al 2000)

4. Summary BH mass of AGNs can be obtained by reverberation mapping, the MBH -  relation and the R-L relation. For (extremely) radio-loud AGNs, using the R-L5100A relation may overestimate the BH mass. The RBLR -emission line luminosity relation is more preferable. For blazar-type AGNs with weak/no emission lines, we can estimate the BH mass from the fundamental plane of their elliptical hosts and the MBH -  relation These methods can be applied to high-z quasars