FORMATION OF SUPERMASSIVE BLACK HOLESFORMATION OF SUPERMASSIVE BLACK HOLESNestor M. Lasso CabreraNestor M. Lasso Cabrera

In this presentation the different theories that can explain theIn this presentation the different theories that can explain theformation of formation of SupermassiveSupermassive Black Holes (SMBH) are presented. Black Holes (SMBH) are presented. Before focus on these theories, an introduction to Black Hole (BBefore focus on these theories, an introduction to Black Hole (BH) H) and SMBH properties is given, along with a brief explanation of and SMBH properties is given, along with a brief explanation of the the different techniques used to find SMBH.different techniques used to find SMBH.

Also a description of what we know about SMBH is in here. In Also a description of what we know about SMBH is in here. In this part are of remarkably importance the facts that:this part are of remarkably importance the facts that:

High Z and Low Z quasar have similar properties: Then they High Z and Low Z quasar have similar properties: Then they should have a common origin.should have a common origin.

Mass of SMBH proportional to the mass of the bulge: Mass of SMBH proportional to the mass of the bulge: Exceptions M33 and NGC205. Exceptions M33 and NGC205.

The formation of SMBH is a not clear process. It has not been The formation of SMBH is a not clear process. It has not been explained yet what was first: Stars or explained yet what was first: Stars or BH’sBH’s, the Galaxy or the central , the Galaxy or the central SMBH. Here the three most plausible explanation of formation of SMBH. Here the three most plausible explanation of formation of SMBH are given:SMBH are given:

Population III stars: Accretion, Mergers or Accretion + MergersPopulation III stars: Accretion, Mergers or Accretion + MergersCollapse of Gas CloudsCollapse of Gas CloudsCollapse of Stellar ClustersCollapse of Stellar Clusters

1. Population III stars:1. Population III stars:

A. Accretion:A. Accretion:

The process is thought to start with a Population III star as a The process is thought to start with a Population III star as a seed seed in the earlier Universe. These stars collapse at the end of theiin the earlier Universe. These stars collapse at the end of their lives r lives to form to form BH’sBH’s. These . These BH’sBH’s emitting at emitting at EddingtonEddington luminosity and luminosity and accreting gas at accreting gas at EddingtonEddington limit with a efficiency of 10% would last limit with a efficiency of 10% would last about 7x108 yrs. to become a SMBH of mass 3x109 Mabout 7x108 yrs. to become a SMBH of mass 3x109 M . SMBH at . SMBH at high Z cannot be explained by this theory.high Z cannot be explained by this theory.

A plausible explanation for these A plausible explanation for these SMBH’sSMBH’s at high Z is that someat high Z is that someperiod of time they accrete at Superperiod of time they accrete at Super--EddingtonEddington rate and therate and the

rest of their life at rest of their life at EddingtonEddington rate.rate.

B. Mergers:B. Mergers:

Again the process is thought to star with a Population III star Again the process is thought to star with a Population III star as as a seed in the earlier Universe which collapse and form a BH. Thia seed in the earlier Universe which collapse and form a BH. This s BH will grow by mergers with others BH and Intermediate BH BH will grow by mergers with others BH and Intermediate BH (IBH). The total number of mergers depends on the (IBH). The total number of mergers depends on the mass of Seeds mass of Seeds and the mass of Dark Matter Halos. and the mass of Dark Matter Halos.

In a normal case a total of 102 In a normal case a total of 102 –– 103 dark matter halos are 103 dark matter halos are needed to form a SMBH. This big number tells us that the theory needed to form a SMBH. This big number tells us that the theory is is not valid alone. not valid alone.

C. C. Accretion + Mergers:Accretion + Mergers:

The most plausible theory is the combination of Accretion and The most plausible theory is the combination of Accretion and Mergers. In this case some authors claim that the proportions woMergers. In this case some authors claim that the proportions would uld be: be: 10% Mergers + 90% Accretion 10% Mergers + 90% Accretion

2. Collapse of Gas Clouds:2. Collapse of Gas Clouds:

This theory is based in that a gas cloud can collapse to form a This theory is based in that a gas cloud can collapse to form a SMBH via a SMBH via a supermassivesupermassive star or via a disk. This theory is only valid star or via a disk. This theory is only valid if if fragmentation of the gas cloud into stars can be avoided. fragmentation of the gas cloud into stars can be avoided.

Conditions necessary to avoid star formation in the gas clouds Conditions necessary to avoid star formation in the gas clouds are given, along with a possible outcome for the formation of thare given, along with a possible outcome for the formation of the e SMBH.SMBH.

3. Collapse of Stellar Clusters:3. Collapse of Stellar Clusters:

This theory is based in the possibility of that a stellar clusteThis theory is based in the possibility of that a stellar cluster r collapse to form a SMBH. Conditions necessary for the collapse acollapse to form a SMBH. Conditions necessary for the collapse are re given, so as other possible variation of this theory.given, so as other possible variation of this theory.

FORMATION OF SUPERMASSIVE BLACK HOLES

NESTOR M. LASSO CABRERA

AST 7939High Energy Astrophysics

Jonathan Tan

Outline

What is a Black Hole?What is a SMBH?

How to find SMBH

What do we know about SMBH?

Formation of SMBHPopulation III Stars: Accretion and Mergers

Collapse of Gas Clouds

Collapse of Stellar Clusters

What is a Black Hole?

Stars with M > 5-6 MCeases to sustain a nuclear fusion reaction

Collapses under its own gravitational field

Supernova

Black Hole

Nothing escapes its gravitational field

Well known: Formation

Localization

Mass

What is a SMBH?

SuperMassive Black HoleMass ~ 108 - 109 M

Nothing escapes its gravitational field

NOT well known: Mass

Localization: Center of galaxies ??

Formation ?????????

Quasars

How to find a SMBH?

Radio “Light”Centaurus A

Visible Light

0.8 Mpc

106 - 109 M NO STAR

X-Ray EmissionRadial Velocity

Rotational Velocity

Gravitational lensing

~1350 Km s-1

What do we know about SMBH?Present in nearly all active and non-active luminous galaxiesQuasar populationHigh z and Low z quasar similar properties – indistinguishableMass proportional to the mass of bulgeM ~ 0.2% M galaxy

(Miyaji et al. 2000)

What do we know about SMBH?Mass proportional to the mass of bulge EXCEPTIONS:

M33 and NGC 205 (Ferrarese et al. 2006)

Formation of SMBHNot clear:

First nonlinear objects: Stars or BH ?

Galaxies or Central BH ?

THEORIES:

Population III stars: Accretion

Mergers

Accretion + Mergers

Collapse of Gas Clouds

Collapse of Stellar Clusters

1 - Population III stars: AccretionSeed: Early massive star - Population III stars

Free metal

~100 M (Abel et al. 2002 and Bromm et al. 2002)

BH (Heger et al. 2003 and Carr et al. 1984)

Gas Accretion: Eddington limit = 10 LEdd / c2

Eddington Luminosity LEdd = (4πmpcGM)/σThRadiative Efficiency of 10% η = 0.1

MSMBH = 3x109 M

tSMBH ~ 7x108 yr. (Haiman et al. 2001)

tΛCMD Uni (z=6) ~ 8x108 yr.

SEEDS at z ≥ 15

SMBH at high z NO PAUSIBLE

MEdd

.

1 - Population III stars: AccretionEddington rate:

MBH = 108 M

Radiative Efficiency of 10% η = 0.1

= 10 LEdd / c2 ≈ 1.7 M yr-1

Super-Eddington rate: SMBH at high z PLAUSIBLES

Thick disk (Radiative inefficient flow RIAF)

Eddington luminosity

Energy not radiate away

M >>.

MEdd

.MEdd

.

(Begelman et al. 1982)

1 - Population III stars: Accretion

Super-Eddington rate + Eddington rate (Cavaliere et al. 2000)

If Outflows of mass

Little mass reach the BH (Stone et al. 1999)

SMBH at high z NO PAUSIBLE

(Begelman 2002)

SMBH at high z PAUSIBLE

M >>.

MEdd

.

M ~ 10 -100.

MEdd

.

1 - Population III stars: Mergers

Seed: Early massive star - Population III starsFree metal

z ~ 20

In dark matter halos of 106 M (min. to form stars)

~100 M (Abel et al. 2002 and Bromm et al. 2002)

BH (Heger et al. 2003 and Carr et al. 1984)

Mergers: Total Mergers depend on: mass of Seeds and mass of Dark Matter Halos

Mergers of ~ 104 IMBH (105 M ) 102 – 103 Dark Matter Halos

NO VALID ALONE

1 - Population III stars: MergersNGC 6240

First evidence of SMBH Mergers

3000 light years apart

1 - Population III stars: Accretion + Mergers

10% Mergers

90% Accretion

(Combes 2005)

2 – Collapse of Gas Clouds

Could form SMBH’s directly at high z via:Supermassive Star (SMS)

Disk

Only if fragmentation of the gas cloud into stars can be avoided

Contracting gas becomes:Optically thick

Radiation pressure supported

If self-gravitating Prone to Star Formation (Goodman 2003)

Less susceptible to Star Formation(Loeb et al. 1994)

2 – Collapse of Gas CloudsHow to stabilize the cloud and avoid Star Formation?

Keep disk at high temperature:Only in metal free, high z halos

H2 dissociated by UV light

No cooling

No molecules No star formation

Gas collapses at ~ 8000K

~ 106 M SMBH (Oh et al. 2003)

Angular momentum (even with cooling particles):From gravitational instabilities, spiral waves, bars, …

Drive a fraction of the gas to smaller scales in nucleus

2 – Collapse of Gas Clouds

A possible outcome for the formation of the SMBH:

Gas flows inDisk becomes optically thickRadiation pressure dominates for sufficiently massive objectsRadiation pressure may temporarily balance gravityForming a SMS SMS radiates at Eddington limit and continue contractingWhen SMS sufficiently compact, star becomes dynamically unstableFor M ≤ 105 M Start stops collapsing and explodeFor M > 105 M Start collapses directly to a SMBH (Shapiro 2004)

3 – Collapse of Stellar Clusters

Negative heat capacity of self-gravitating stellar systems makes them

vulnerable to gravitational collapse (Binney & Tremaine 1987)

If core collapse continues SMS SMBHDepends on number of stars in cluster N ≥ 106 – 107 stars (Lee 1987)

A different theory: (Begelman et al. 1978)

Massive stars dominate the dynamics of the cluster

Massive stars collapse faster than cluster as a whole

IMBH

IMBH + Accretion + Mergers

References:

Haiman, Z. 2004 arXiv:astro-ph/0403225v1

Greenwood, C.J. “Supermassive Black Holes at the Center of Galaxies

Kormendy et al. 2001 arXiv:astro-ph/0105230v1

Miyaji, T., Hasinger, G., & Schmidt, M. 2000, A&A, 353, 25

Begelman, M. C., & Meier, D. L. 1982, ApJ, 253, 87

Combes, F. 2005 arXiv:astro-ph/0505463

THE LOW MASS END OF THE THE LOW MASS END OF THE SUPERMASSIVE BLACK HOLE POPULATIONSUPERMASSIVE BLACK HOLE POPULATION

M33M33Nestor M. Lasso CabreraNestor M. Lasso Cabrera

This presentation is base in the low mass end of the SMBH This presentation is base in the low mass end of the SMBH population. In particular it is based on M33 and its particular population. In particular it is based on M33 and its particular nuclei.nuclei.

After see in the former presentation the particularities of the After see in the former presentation the particularities of the nuclei of M33 compare with other luminous galaxies, here is nuclei of M33 compare with other luminous galaxies, here is presented a study of M33 compare with M32, a galaxy with bulge, presented a study of M33 compare with M32, a galaxy with bulge, and with NGC4395, a similar galaxy with bulge.and with NGC4395, a similar galaxy with bulge.

Curves of Curves of Surface brightness profile, radial velocity and velocity Surface brightness profile, radial velocity and velocity dispersion of M33 are compared with that of M32, a typical galaxdispersion of M33 are compared with that of M32, a typical galaxy y with bulge. This curves place the upper limit of M33 in 3000Mwith bulge. This curves place the upper limit of M33 in 3000M for for MerritMerrit et al.,2001 and in 1500 et al.,2001 and in 1500 MM for for GebhardtGebhardt et al., 2001.et al., 2001.

Also the relation mass BH vs. velocity dispersion is shown for Also the relation mass BH vs. velocity dispersion is shown for different galaxy and both upper limits of M33 are place in the pdifferent galaxy and both upper limits of M33 are place in the plot, lot, showing that M33 does not follow the relation.showing that M33 does not follow the relation.

Finally M33 is compare with NGC 4395. A galaxy pretty similar Finally M33 is compare with NGC 4395. A galaxy pretty similar to M33 but that shows a BH of about 3to M33 but that shows a BH of about 3--4 x 105M4 x 105M ..

THE LOW MASS END OF THESUPERMASSIVE BLACK HOLE

POPULATION

M33

NESTOR M. LASSO CABRERA

AST 7939High Energy Astrophysics

Jonathan Tan

FORMATION OF SUPERMASSIVE BLACK HOLESWhat is a SMBH?How to find SMBH

X-Ray Emission

Radial VelocityRotational VelocityGravitational Lensing

What do we know about SMBH?Present in almost all luminous galaxies

Quasar PopulationHigh and Low z quasar with similar propertiesMass proportional to the mass of bulgeM ~ 0.2% M galaxy

FORMATION OF SUPERMASSIVE BLACK HOLES

Formation of SMBHPopulation III Stars: Accretion and MergersCollapse of Gas CloudsCollapse of Stellar Clusters

Mass proportional to the mass of bulge EXCEPTIONS:M33 and NGC 205

(Ferrarese et al. 2006)

Brightest Galaxies => SMBHIntermediate and Lowest Galaxies => Stellar Nucleus 50%-70% late-type galaxies contain Stellar Nucleus (Balcells et al. 2003)

Stellar Nuclei ~20 times brighter than typical globular cluster

M33

Michard & Nieto, 1991Gebhardt et al., 2001

Surface brightness profile

M32

Merrit et al.,2001 Gebhardt et al., 2001 Bender, Kormendy & Dehnen 199621km/s ≤ σ ≤ 35km/s σ ~ 24km/s

M• ≤ 7x104 Mּס M• ≤ 5x104 Mּס

Upper limit: M• ≤ 3000 Mּס M• ≤ 1500 Mּס

M33 M33 M32

Merrit et al.,2001

Gebhardt

M•=1.3x108 Mּס (σ/200)4.8 Ferrarese & Merrit 2000M•=1.3x108 Mּס (σ/200)3.65 Gebhardt et al., 2001

σ < 35Km/s ~ Glob. cluster σ => No evidence BH (Merrit et al., 2001)

σ ~ 24Km/s ~ Glob. cluster σ => No evidence BH (Gebhardt et al., 2001)

Upper limit on the Mass ~3000M Merrit et al.,2001

Upper limit on the Mass ~1500M Gebhardt et al.,2001

Stellar central ρ ~ 106 M /pc3 ~ BH ρ >> Globular cluster ρ

Stellar Nuclei ~20 times brighter than typical globular cluster

NO BH or Globular cluster in Bulgeless galaxies => WHAT????

Barth et al. 2005

Filippenko & Ho, 2003

σ ≤ 30km/sTHERE IS A BH!!!

M• ~ 3-4x105 MּסReverberation Mapping

Conclusions

Some Bulgeless galaxies have BH

Other Bulgeless galaxies: NO BH or Globular cluster

=> WHAT????

Luminous Galaxies with Bulge (L, σ ): SMBH

M• - σ relation for luminous galaxies with bulges

M• - σ relation for bulgeless galaxies ????

References:

Ferrarese et al. 2006, ApJ 644,L21

Merritt et al. 2001, arXiv:astro-ph/0107359v2

Gebhardt et al. 2001, ApJ 122:2469

Greene and Ho 2007, arXiv:astro-ph/0707.2617v1

Barth et al. 2005, ApJ 619:L151