1. Why Massive Black Holes Why Massive Black Holes are Small in Disk Galaxies ? are Small in Disk Galaxies ? Formation of the First Generation of Galaxies: Strategy for the Observational Corroboration of Physical Scenarios, 2-5 December 2003, Niigata University, Niigata, Japan Nozomu KAWAKATU Center for Computational Physics, University of Tsukuba Masayuki UMEMURA Collaborator Center for Computational Physics, University of Tsukuba

2. Contents Introduction Physical mechanism for formation of Supermassive Black Holes Model for Disk galaxies Radiation drag (Poynting-Robertson) effect Basic Equation Results Summary Recent observational results ( BH mass-to-bulge mass correlation ) Angular momentum transfer problem for supermassive black holes Equation of angular momentum transfer Treatment for extinction by dusty gas Relationship between the final BH mass and bulge-to-disk ratio of host galaxy

3. Introduction Recent high quality observations of galactic centers 1) BH mass-to-galaxy mass ratio is considerably smaller than 0.002 for Disk. (Salucci et al. 2000; Sarzi et al. 2001; Ferrarese 2002; Baes et al. 2003) 0.1 1 10 -4 10 -3 M BH / M galaxy 0.03 10 -2 10 -5 Normal spiral and barred galaxies Sy1 × ▲ NLSy1 Sy2 2) BH mass-to-galaxy mass ratio is reduced by more than an order of magnitude with a smaller bulge-to-disk ratio.

4. 0.1 1 10 -4 10 -3 M BH / M bulge 0.03 10 -2 10 -5 Normal spiral and barred galaxies Sy1 × ▲ NLSy1 Sy2 3) BH mass-to-bulge mass ratio lies at a level of 0.001, which is similar to that found in elliptical galaxies. Formation of SMBHs Formation of Bulges Physical relation! = (e.g., Kormendy & Richstone 1995) ellipticals

5. It has not been clear why the BH mass is smaller in disk physically!! Elliptical Galaxies Disk Galaxies Summary of observational results in galactic centers

6. The physics on the angular momentum transfer is essential ! SMBH Formation: Angular Momentum Problem Hydrodynamical Mechanisms for Ang. Mom. Transfer ( From galactic scale to BH horizontal scale ) 1) Gravitational torque by a bar or non-axisymmetric mode But, this mechanism is effective only beyond ~ 1kpc. 2) Turbulent viscosity But, the timescale is longer than the Hubble time in galactic scale ! (e.g. A galactic disk cannot shrink via turbulent viscosity.) (Wada & Habe 1995, Fukuda 1998) 3) Radiation drag (present work) The timescale is shorter than the Hubble time in galactic scale. theoretical upper limit: (Umemura 2001)

7. Radiation Drag – Poynting-Robertson Effect – Lab.Frame v0v0 Lab.Frame Matter slowdowns ! v0v0 v < v “radiation drag”  In practice, optically thin surface layer is stripped by radiation drag, and loses angular momentum (Sato-san talks in details).

8. 1) The BH-to-bulge mass ratio is basically determined by the energy conversion efficiency of nuclear fusion from hydrogen to helium, i.e., 0.007. Radiation Drag efficiency in galactic bulges Radiation Drag efficiency in galactic bulges (Umemura 2001) “Radiation drag efficiency is determined by the total number of photons ” :total luminosity of the bulge 2) The inhomogeneity of ISM helps the radiation drag to sustain the maximal efficiency. 3) By incorporating the realistic chemical evolution, we predicted. (Kawakatu & Umemura 2002 ) (Kawakatu, Umemura & Mori 2003 ) ISM is observed to highly inhomogeneous in active star-forming galaxies ! covering factor O(1) Optically thick regime

9. Radiation drag - Geometrical Dilution - (Umemura et al. 1997,1998; Ohsuga et al. 1999) low drag efficiency high drag efficiency Spherical System Disk-like System However, the details are not clear quantitatively !

10. This Work We investigate the efficiency of radiation drag in disk galaxies. To investigate the relation between the morphology of host galaxies and the angular momentum transfer efficiency due to the radiation drag We solve the 3D radiation transfer in an inhomogeneous ISM. We have disclosed the physical reasons why the BHs are smaller in disk galaxies! why the BHs are smaller in disk galaxies!

11. Model The difference of morphology is expressed by changing “ bulge fraction (f bulge )”. 1 0.03 0.5 f bulge “disk scale height “ Inhomogeneous ISM covering factor is unity.

12. Basic Equations The gain and loss of total angular momentum is regulated by this equation. The Eq.of Ang.Mom.Transfer Radiation Drag Radiation Flux ： mass extinction due to dust opacity radiation energy densityradiation flux radiation stress tensor The contribution of the radiation from distant stars is essential to radiation drag since these stars have different velocities from absorbing clouds.

13. Treatment of the radiation tranfser :optical depth of a gas cloud ： the optical depth for all intervening clouds along the light ray opacity : dust in clumpy gas clouds All radiative quantities are determined by radiation from stars diluted by dusty ISM. We calculate the radiation fields by the direct integration of the radiation transfer.

14. Mass Accretion Rate Total mass of the ISM Angular Momentum Extraction Estimate for BH mass Angular momentum transfer in an Inhomogeneous ISM ( t 0 :Hubble time; J: total angular momentum ) Total angular momentum loss rate ( N c :Number of clouds)

15. ～ 1/20 ～ 1/50 ～ 1/200 0.11 10 -4 10 -3 Mass ratio 0.03 10 -5 Sd Sc SbSa S0 E Hubble Type Almost constant Result.1: BH mass-to-morphology relation

16. Why MBH are small in disk galaxies ？ ① & ② Radiation drag cannot work effectively in disk galaxies ! pole on view ③ “radiation” ② Radiation from disk stars is heavily diminished across the disk (optically thick disk) ① A number of photons escaped from the system (Surface-to-volume ratio ) ③ The velocity difference stars and absorbing clouds becomes closer to zero (optically thick disk)

17. 0.1 1 10 -4 10 -3 M BH / M galaxy NGC3245 NGC4151 NGC3516 NGC5548 NGC4593 NGC7469 Mrk590 NGC3783 3C120 NGC4051 Mrk509 M81 NGC 1023 M31 Fairall 9 Galaxy NGC4258 NGC7457 NGC4395 NGC1068 (Sy1/Starburst) NGC3227 (Sy2/Starburst) Circinus (Sy2/Starburst) Normal spiral and barred galaxies Sy1 × ▲ NLSy1 Sy2 0.03 10 -5 10 -2 Result.2-1: Comparison with the observations Normal spiral and barred galaxies Sy1 × NGC3245 NGC4151 NGC3516 NGC5548 NGC4593 NGC7469 Mrk590 NGC3783 3C120 NGC4051 Mrk509 M81 NGC 1023 M31 Fairall 9 Galaxy NGC4258 NGC7457 NGC4395 NGC1068 (Sy1/Starburst) ▲ NLSy1 NGC3227 (Sy2/Starburst) Circinus (Sy2/Starburst) Sy2 Normal spiral and barred galaxies Sy1 × NGC3245 NGC4151 NGC5548 NGC4593 NGC3783 Mrk509 M81 NGC 1023 M31 Fairall 9 Galaxy NGC4258 NGC7457 NGC4395 ▲ NLSy1 NGC3227 (Sy2/Starburst) NGC7469 Mrk590 3C120 NGC4051 NGC1068 (Sy1/Starburst) (Sy2/Starburst) Circinus (Sy2/Starburst) Sy2 This trend is broadly consistent with theoretical prediction. These objects have relatively small BHs compared with the predictions.

18. Result.2-2: Comparison with the observations 0.11 10 -4 10 -3 M BH / M bulge NGC3245 NGC4151 NGC3516 NGC5548 NGC4593 NGC7469 Mrk590 NGC3783 3C120 NGC4051 Mrk509 M81 NGC1023 M31 Fairall 9 Galaxy NGC4258 NGC7457 NGC4395 NGC1068 (Sy1/Starburst) NGC3227 (Sy2/Starburst) Circinus (Sy2/Starburst) Normal spiral and barred galaxies × NLSy1 Sy2 ▲ 0.03 Sy1 10 -2 10 -5 NGC3245 NGC4151 NGC3516 NGC5548 NGC4593 NGC7469 Mrk590 NGC3783 3C120 NGC4051 Mrk509 M81 NGC1023 M31 Fairall 9 Galaxy NGC4258 NGC7457 NGC4395 NGC1068 (Sy1/Starburst) NGC3227 (Sy2/Starburst) Circinus (Sy2/Starburst) Normal spiral and barred galaxies × NLSy1 Sy2 ▲ Sy1 NGC3245 NGC4151 NGC3516 NGC5548 NGC4593 NGC7469 Mrk590 NGC3783 3C120 NGC4051 Mrk509 M81 NGC1023 M31 Fairall 9 Galaxy NGC4258 NGC7457 NGC4395 NGC1068 (Sy1/Starburst) NGC3227 (Sy2/Starburst) Circinus (Sy2/Starburst) Normal spiral and barred galaxies × NLSy1 Sy2 ▲ Sy1 Observational data roughly agree with the prediction. Sy1 with SB & NLSy1 fall appreciably below 0.001 again.

19. Summary １． BH-to-galaxy mass ratio decreases with a smaller bulge-to-disk ratio, and is reduced maximally by two orders of magnitude, resulting in. Almost all photons can escape from a disk-like system, owing to the effect of geometrical dilution. The radiation from stars in disk galaxies is considerably reduced in the optically-thick disk. ＜ Physical Reasons ＞ ２． In disk galaxies, the BH-to-bulge mass ratio is about 0.001. The BH-to-bulge mass ratio is fundamentally determined by physical constantε=0.007, regardless of morphology of host galaxies. It turns out that the formation of SMBH is not basically determined by disk components, but bulge components, consistently observational data. The present model also predict BH-to-galaxy mass ratio depends on the disk scale-height (h), The velocity difference stars and absorbing clouds becomes closer to zero

20. Grazie mille! どうもありが とう ございました！