How do galaxies accrete their mass? Quiescent and star - forming massive galaxies at high z
Why Massive Black Holes are Small in Disk Galaxies ?
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Transcript of Why Massive Black Holes are Small in Disk Galaxies ?
Why Massive Black HolesWhy 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
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 transferTreatment for extinction by dusty gas
Relationship between the final BH mass and bulge-to-disk ratio of host galaxy
IntroductionRecent high quality observations of galactic centers1) 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
bulge galaxyM M
MB
H /
Mga
laxy
0.03
10-2
10-5
Normal spiral and barred galaxies
Sy1
×▲ NLSy1Sy2
2) BH mass-to-galaxy mass ratio is reduced by more than an order of magnitude with a smaller bulge-to-disk ratio.
0.1 1
10-4
10-3
bulge galaxyM M
MB
H /
Mbu
lge
0.03
10-2
10-5Normal spiral and barred galaxies
Sy1
×▲ NLSy1Sy2
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!Physical relation!
=
(e.g., Kormendy & Richstone 1995)
ellipticals
It has not been clear
why the BH mass is smaller in disk physically!!
BH galaxy 0.002M M
BH galaxy 0.002M M
Elliptical Galaxies
Disk Galaxies
BH bulge( 0.002)M M
Summary of observational results in galactic centers
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.)
1 21 11 210
vis kpc2 11 4s
3 10 yr0.1 10 10
j M Tt R
c M K
¤
(Wada & Habe 1995, Fukuda 1998)
3) Radiation drag (present work)
The timescale is shorter than the Hubble time in galactic scale.1 12 2
27drag kpc12
8.6 10 yr10
c R L Zt R
L L Z
¤ ¤
BH galaxy max0.007M M theoretical upper limit: (Umemura 2001)
Radiation Drag – Poynting-Robertson Effect –
< Absorption process >
Lab.Frame
2 2final mc t m c
final final
t v
mv m vc c
m0
v0
E t
finalm
finaalv
t vp
c c
< Re-emission process >
Lab.Frame
final 0 ,m m final v vMatter slowdowns ! v0v <
m
v“radiation drag”
E t
2 20 mc t mc
0 0 mv mv
In practice, optically thin surface layer is stripped by radiation drag, and loses angular momentum (Sato-san talks in details).
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)
bulgeBH 2
LM dt
c
“Radiation drag efficiency is determined by the total number of photons ”
bulgeL :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
BH bulge 0.002M M
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 !
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 reasonsWe have disclosed the physical reasons
why the BHs are smaller in disk galaxies!why the BHs are smaller in disk galaxies!
Model
bulge bulge galaxyf M M
The difference of morphology is expressed by changing “ bulge fraction (fbulge)” .
1
0.03
0.5 fbulge
11galaxy( 10 )M M ¤
disk disk0.01 0.1h r r “disk scale height “
Inhomogeneous ISM covering factor is unity.
Basic Equations
The gain and loss of total angular momentum is regulated by this equation.
1( )
d rvF E P v
r dt c c
The Eq.of Ang.Mom.Transfer
Radiation DragRadiation Flux
:F :P:E d d gn : mass extinction due to dust opaci
tyradiation energy density radiation 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.
Treatment of the radiation tranfser
-,0 er
jdF
0, 0, 0,1 1 1
, ,N N N
j j jj j j
e E dE e P dP e
F dF
1 22
c2 1 b r
gas cr :optical depth of a gas cloud
: the optical depth for all intervening clouds along the light ray
,0r
jdF
b
cr
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.
Mass Accretion Rate
g g
JM M
J
Total mass of the ISM
Angular Momentum Extraction
Estimate for BH mass
0 0
BH g g0 0
t t JM M dt M dt
J
Angular momentum transfer in an Inhomogeneous ISM
( t0:Hubble time; J: total angular momentum )
dragrot
1
( )cN
i i ii
J r F Fc
Total angular momentum loss rate
( Nc:Number of clouds)
~ 1/20
~ 1/50
~ 1/200
disk0.01h r
disk0.04h r
disk0.1h r
BH galaxyM M
0.1 1
10-4
10-3
Mas
s ra
tio
bu lge bulge galaxyf M M0.03
10-5
Sd Sc Sb Sa S0 EHubble Type
BH bulgeM M
BH galaxyM M
disk0.01h rdisk0.04h r disk0.1h r
disk0.01h r
disk0.04h r
disk0.1h r
Almost constant
Result.1: BH mass-to-morphology relation
3BH galaxy bu lge10M M f
Why MBH are small in disk galaxies? ① & ②
Radiation drag cannot work effectively in disk galaxies !
pole on viewpole 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)
0.1 1
10-4
10-3
bulge galaxyM M
MB
H /
Mga
laxy
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)
(Sy2/Starburst)
Circinus (Sy2/Starburst)
Normal spiral and barred galaxiesSy1
×▲ NLSy1Sy2
0.03
10-5
10-2
Result.2-1: Comparison with the observations
Normal spiral and barred galaxiesSy1
×
NGC3245
NGC4151
NGC3516
NGC5548
NGC4593
NGC7469Mrk590
NGC3783
3C120
NGC4051
Mrk509
M81
NGC1023
M31
Fairall 9
Galaxy
NGC4258
NGC7457
NGC4395
NGC1068
(Sy1/Starburst)
▲ NLSy1NGC3227
(Sy2/Starburst)
(Sy2/Starburst)
Circinus (Sy2/Starburst)
Sy2 Normal spiral and barred galaxiesSy1
×
NGC3245
NGC4151
NGC5548
NGC4593
NGC3783
Mrk509
M81
NGC1023
M31
Fairall 9
Galaxy
NGC4258
NGC7457
NGC4395
▲ NLSy1NGC3227
(Sy2/Starburst)
NGC7469Mrk590
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.
Result.2-2: Comparison with the observations
0.1 1
10-4
10-3
bulge galaxyM M
MB
H /
Mbu
lge
NGC3245NGC4151
NGC3516
NGC5548
NGC4593
NGC7469
Mrk590
NGC3783
3C120
NGC4051
Mrk509
M81
NGC1023
M31
Fairall 9
Galaxy
NGC4258
NGC7457
NGC4395
NGC1068
(Sy1/Starburst)
NGC3227
(Sy2/Starburst)
(Sy2/Starburst)
Circinus (Sy2/Starburst)
Normal spiral and barred galaxies×NLSy1Sy2 ▲
0.03
Sy1
10-2
10-5
NGC3245NGC4151
NGC3516
NGC5548
NGC4593
NGC7469Mrk590
NGC3783
3C120
NGC4051
Mrk509
M81
NGC1023
M31
Fairall 9
Galaxy
NGC4258
NGC7457
NGC4395
NGC1068
(Sy1/Starburst)
NGC3227
(Sy2/Starburst)
(Sy2/Starburst)
Circinus (Sy2/Starburst)
Normal spiral and barred galaxies×NLSy1Sy2 ▲Sy1
NGC3245NGC4151
NGC3516
NGC5548
NGC4593
NGC7469Mrk590
NGC3783
3C120
NGC4051
Mrk509
M81
NGC1023
M31
Fairall 9
Galaxy
NGC4258
NGC7457
NGC4395
NGC1068
(Sy1/Starburst)
NGC3227
(Sy2/Starburst)
(Sy2/Starburst)
Circinus (Sy2/Starburst)
Normal spiral and barred galaxies×NLSy1Sy2 ▲Sy1
Observational data roughly agree with the prediction .Sy1 with SB & NLSy1 fall appreciably below 0.001 again.
Summary1. 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 The BH-to-bulge mass ratio is fundamentally determined by physical constantε=0.007, regardless of morphology of host galaxies.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.
5BH galaxy 10M M
The present model also predict BH-to-galaxy mass ratio depends on the disk scale-height (h), 3
BH galaxy disk10 / 2M M h r
• The velocity difference stars and absorbing clouds becomes closer to zero
Grazie mille!どうもありがとう ございました!