supermassive black holes in radio-loud agns

Click here to load reader

Post on 30-Dec-2015

38 views

Category:

Documents

0 download

Embed Size (px)

DESCRIPTION

Supermassive Black Holes in Radio-loud AGNs. Xue-Bing WU (Peking Univ.). Collaborators: PKU: FuKun Liu, Ran Wang NAOC: JinLin Han, MinZhi Kong. 1. Introduction. Supermassive black holes in nearby galaxies (mass determined by stellar, gas, & water maser dynamics) - PowerPoint PPT Presentation

TRANSCRIPT

  • Supermassive Black Holes in Radio-loud AGNsXue-Bing WU (Peking Univ.)

    Collaborators: PKU: FuKun Liu, Ran WangNAOC: JinLin Han, MinZhi Kong

  • Supermassive black holes in nearby galaxies (mass determined by stellar, gas, & water maser dynamics)(Kormendy & Richstone 1995; Kormendy & Gebhardt 2001; Ho 1999) Supermassive black hole formation is closely related to galaxy formation 1. Introduction Tremaine et al.(2002)MBH 4

  • AGN Structure

    Supermassive black hole Accretion diskBroad line regionDusty torusNarrow line regionJet

  • Black hole mass estimations of AGNs

    Direct methods

    Stellar dynamics: not feasible, since the AGN is too bright.

    Gas kinematics: only in a few cases, if the gas is seen in Keplerian rotation. In M87, r=75 pc disk yields 3 109 Msun

    Megamasers: only in several edge-on Sy2s. In NGC4258, 0.02 pc resolution gives perfect Keplerian rotation. 3.6 107 Msun

  • Indirect MethodsAccretion disk fitting of the big blue bump in the UV/optical spectra of AGNStandard thin disk model (Shakura & Sunyaev 1973):

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

  • Broad emission line region: 0.01 - 1pc; The AGN's photoionizing continuum radiation is reprocessed 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 tV estimated by the FWHM of broad emission line

    Reverberation mapping from optical variabilityPeterson (1997)MrK 335: t=15.6 days

  • BLR Scaling with Luminosity Photoionization model prediction

    Same ionization parameter Same density

    With the empirical R-L relation, we can estimate the BLR size from the optical continuum luminosityKaspi et al. (2000)

  • SMBH and Galactic BulgeRelations of black hole mass with bulge luminosity and central velocity dispersion (for both normal galaxies & AGNs)Ferrarese et al. (2001)AGNWith the MBH - relation, we can estimate the BH mass of AGNs from the measured stellar velocity dispersion

  • 2. 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)

  • For radio-loud AGNs, optical continuum luminosity may be significantly contributed from jets, thus 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

    3C 273

  • An empirical relation between the BLR size and emission line luminosity (Spearmans rank r=0.91)Comparison of the results obtained with two R-L relations : Using the R-L5100A relation may overestimate MBH for radio-loud quasars!

  • Recently we also extended such a study to UV broad emission lines (Kong, Wu, Wang, & Han 2005, A&A )

  • 3. SMBH Mass of AGNs with elliptical host (Wu, Liu & Zhang, 2002, A&A, 389, 742)Reverberation mapping can not apply to BL Lacs, a subclass of radio-loud AGNs without/with weak emission linesOnly a dozen of BL Lacs have measured values and the estimated SMBH masses: 5E7 to 1E9 solar masses (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

  • Fundamental plane of elliptical galaxies(Bettoni et al. 2001)(Djorgovski & Davis 1987; Dressler et al. 1987; Faber et al. 1989; Jorgensen et al. 1996)

  • SMBH Masses of AGNs with E hostSample 1: 63 BL Lacs (51 HBLs; 12 LBLs) with known redshift from HST snapshot survey (Urry et al. 2001). No significant difference in SMBH masses between HBLs & LBLsSample 2: HST imaging sample of 10 RGs, 10 RLQs & 9 RQQs with elliptical hosts (McLure et al. 1999; Dunlop et al. 2002). SMBH masses of RQQs are slightly less than those of RLQs; different from previous claims

  • Comparison of Eddington ratios of AGNsThe Eddington ratios (dimensionless accretion rates) of radio galaxies are about two orders lower than those of quasars.Radio galaxyQuasars

  • 4. Discussion & Summary Knowing the BH mass is important and helpful to other AGN studiesSD: 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)Accretion disk structure is strongly dependent on the accretion rate

  • A fundamental plane of black hole activity(Merloni et al. MNRAS, 2003)

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

  • Summary Supermassive black holes with mass of 106 to 109 solar masses exist in the center of both normal and active galaxies Dynamic methods of estimating the BH mass can only be applied to several nearby AGNs. Reliable BH mass of AGNs (including RL AGNs) can be obtained by reverberation mapping, MBH - relation and two empirical R-L relations BH mass study is important and helpful to other AGN studies (accretion rate; BH spin; jet)