Black Hole - Bulge Relation of High Redshift Quasars

Xue-Bing Wu

(Dept. of Astronomy, Peking University)

Outline

Black Hole Mass Determinations Black Hole - Bulge Relation High-z Quasars Comparison with PG Quasars Discussions

1. Black Hole Mass Determinations

Supermassive Black Holes in the Center of Nearby Galaxies (Kormendy & Gebhardt 2001; Ho 1999)

• Stellar dynamicsMass determined by the rotational velocity V and the velocity dispersion of stars

• Gas dynamicsKeplerian rotation of ionized gas in a disk-like configuration

• Water maser dynamics22 GHz microwave emission from extragalactic water masers

Stellar DynamicsOur Galaxy (Genzel et al. 1997,2003; Ghez et al. 1998,

2005) M*=(3~4) E6 Msun

Stellar velocity & proper motions around Sgr A* yield a BH mass of (3~4) 106 Msun

Estimate the BH mass of AGNs: a difficult task

Direct dynamical methods•Stellar dynamical studies not feasible in AGN, since the AGN is so bright to outshine the stars. • Can use gas and megamaser dynamics only for several nearby AGNs (M87, NGC4258,…)

Indirect methods• Fitting the observed ‘big blue bump’ in the UV/optical spectra

•depends on other parameters: accretion rate, disk inclination, ...

• Fitting the iron K line in the X-ray spectra

•depends on other parameters: emissivity law, inclination, BH spin, ...

– Broad line region (BLR): 0.01 - 1pc; emission lines are produced by the illumination of the AGN's photoionizing continuum radiation

– BLR size can be estimated by the time delay that corresponds to the light travel time between the continuum source and the line-emitting gas: RBLR =c t

– BLR characteristic velocity V can be estimated by the width (FWHM) of broad emission line 2

BLRBH

V RM

G

Reverberation mapping from optical/UV variability

Peterson (1997)

BLR Scaling with LuminosityBLR Scaling with Luminosity

A simple photoionization model predicts:

Consistent with the reverberation mapping results

r L1/2

With the R-L relation, from the optical continuum luminosity we can estimate the BLR size and then BH mass of AGNs

r L0.6±0.1

SMBH in the highest redshift quasar SDSS J114816.64 + 525150.3 (z=6.42)

Willott et al. (2003) (UKIRT/UIST)

FWHM(MgII)=6000km/s MBH=3E9 Msun

Barth et al. (2003) (Keck II/NIRSPEC)

FWHM(MgII)=5500km/s MBH=2E9 Msun

FWHM(CIV)=9000km/s MBH=6E9 Msun

2. Black Hole - Bulge Relation Black hole mass / bulge

mass ~ 0.006 (0.002) (Maggorian et al. 1998, AJ, 115, 2285 )

Is the ratio constant? Is it different for different types of galaxies (Wandel 2002; Laor 2001; Wu & Han 2001; Wu, Liu & Zhang 2002)

MBH Mbulge1.74

Black Hole - Bulge Relation Black hole mass - bulge

stellar velocity relation (M - relation) (Gebhardt et al. 2000; Merritt & Ferrarese 2000; Tremaine et al. 2002)

MBH 4

Tremaine et al. (2002)Kormendy & Gebhardt (2002)

Black Hole - Bulge Relation Two of the first works using

the M - relation to estimate AGN BH mass (Wu & Han 2001, A&A, 380, 31; Wu & Han 2001, ApJ, 561, L59)

“Abstract: We estimated black hole masses for 9 Seyfert 1 and 13 Seyfert 2 galaxies in the Palomar and CfA bright Seyfert samples using the tight correlation between black hole mass and bulge velocity dispersion…”

(Woo & Urry 2002, ApJ)

Black Hole - Bulge Relation

Origins of the black hole -bulge relation– Physics tie between BH and galaxy

formation– Feedback scenario (Silk & Rees 1998;

King 2003, 2005;…)– Two-direction starburst feedback model:

Xu, Wu & Zhao (2007 ApJ); Xu & Wu (2007 ApJ)

The obscured growth of central BH at the early growth stage (Xu, Wu & Zhao 2007, ApJ)The outward starburst feedback resists the gravity of dark matter halo while the inward one regulates the growth of the BH. Because the mass of BH is small at early stage, the feedback from BH can’t balance the inward feedback from the starburst. The BH will hide in the thick gas shell and can not be seen in optical band.

BH - bulge relation of AGNs

Ferrarese et al. (2001) Onken et al. (2004)

M - relation of quasars

For quasars: direct measurement of is difficult; =FWHM([OIII])/2.35 is usually adopted (Nelson 2000; Shields et al. 2003); galaxy growth is contemporaneous with black hole growth up to z=2~3

M - relation of SDSS DR3 quasars (1736+158 sources, z<1.2)

Salviander et al. (2007, ApJ)Evolution at hi-z?

Coppin et al. 2008, MNRAS

3. High-z Quasars How about M - relation at Hi-z? Black hole mass of hi-z quasars can be estimated

using the R-L relation (3E9 solar mass for the BH of a quasar at z=6.4)(Willott et al. 2003; Barth et al. 2003)

Different R-L relations (Kaspi et al. 2000,2005; Vestergaard et al. 2002; McLure & Dunlop 2002; Wu et al. 2004, A&A)

How to estimate at hi-z?– Direct measurement? No– Using narrow line such as [OIII]? No

High-z Quasars

CO molecular emissions have been detected in a number of hi-z quasars, including SDSS J114816.64 + 525150.3 (z=6.42)

Walter et al. (2004, ApJL)

High-z Quasars

CO molecular line detected for a number of hi-z quasars (Solomon & Vanden Bout 2005 ARA&A)

CO line width as a surrogate for (Shields et al. 2006 ApJ, 641, 683)

=FWHM(CO)/2.35

Hi-z quasars, outliers??

(Shields et al. 2006)

High-z Quasars Can we use

=FWHM(CO)/2.35 ?? A test with CO detected 33

Seyfert galaxies (Wu 2007, ApJ, 657, 177)

A better correlation using inclination-corrected line width

CO molecular disk coplanar with the galaxy disk (Heckman et al. 1989)

Wu (2007, ApJ)

High-z Quasars

Assuming inclination ~15o of hi-z quasars, we can re-estimate values using the inclination-corrected CO line width and study the M - relation at Hi-z

Wu (2007, ApJ)

High-z Quasars Small inclinations

(~15o) are also probably needed to explain the narrowness of CO line of hi-z quasars compared with the sub-millimeter galaxies (SMG) (Greve et al. 2005; Carilli & Wang 2006) Carilli & Wang (2006,AJ)

Recent simulations on the morphology and line profile of hi-z quasars (Narayanan et al. 2007)

4. Comparison with PG Quasars Most PG quasars

seem to follow the M - relation (Shields et al. 2006)

Are two narrow CO PG quasars the outliers?

PG 0838+770(FWHM =60km/s) and PG 1415+451(FWHM=90km/s) (Evans et al. 2006)

(Shields et al. 2006)

Two Narrow CO PG Quasars

PG 1415+451(FWHM(CO)=90km/s) =11512 km/s (Kauffman et al. 2003,

MNRAS) Clearly, =FWHM(CO)/2.35 If i=15o

Two Narrow CO PG Quasars

Narrow CO PG quasars are almost face-on (<20o)

=FWHM(CO)/2.35 can not apply

They are not outliers of the M - relation (If the proper values can be obtained)

PG quasars with measured Dasyra et al. (2006, ApJ)

• Long integration H-band spectroscopy with VLT

PG quasars with measured M - relation of PG quasars

Dasyra et al. (2006, ApJ)

5. Discussions Black hole - bulge relation for quasars

seems to be consistent with the local one Accurate measurements of BH mass and

stellar velocity dispersion for a large sample of quasars at different redshift are needed

Hi-z quasars ( evolution of the BH – bulge relation?); mm and cm study

Theoretical understandings of the origin (and evolution) of the BH – Bulge relation