Supermassive black holes

1
Supermassive black holes
2
Plan of the lecture

1. General information about SMBHs.
2. Our certain black hole Sgr A.
3. SMBHs from radio to gamma. AGNs.
4. Mass measurements

Main reviews

• arxiv0705.1537, 0907.5213 Supermassive
  Black Holes
• astro-ph/0512194 Constraints on Alternatives
  to Supermassive Black Holes
• astro-ph/0411247 Supermassive Black Holes in
  Galactic Nuclei
• Past, Present
  and Future Research
• arXiv 0904.2615, 1001.3675, 1108.5102 Mass
  estimates (methods)
• arXiv1302.2643 The Mass of Quasars

See also http//qso.lanl.gov/meetings/meet2006/par
ticipate.html
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Some history
The story starts in 60-s when the first quasars
have been identified (Schmidt 1963). Immediately
the hypothesis about accretion onto supermassive
BHs was formulated (Salpeter, Zeldovich, Novikov,
Linden-Bell).
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General info

• All galaxies with significant bulges should have
  a SMBH in the center.
• SMBH are observed already at redshifts z 6 and
  even larger
• Several percent of galaxies have active nuclei
• Now we know tens of thousand of quasars and
  AGNs, all of them can be considered as objects
  with SMBHs
• Measured masses of SMBHs are in the range 106
  1010 solar masses.
• Masses are well-measured for tens of objects.
• The most clear case of a SMBH is Sgr A.

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Sgr A
The case of Sgr A is unique. Thanks to direct
measurements ofseveral stellar orbits it is
possibleto get a very precise value forthe mass
of the central object. Also, there are very
strict limitson the size of the central
object.This is very important taking
intoaccount alternatives to a BH. The star SO-2
has the orbitalperiod 15.2 yrs and the
semimajoraxis about 0.005 pc. See
astro-ph/0309716 for some details
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The region around Sgr A
The result of sumamtion of 11 expositionsby
Chandra (590 ksec). Red 1.5-4.5 keV, Green
4.5-6 keV, Blue 6-8 keV. The field is 17 to 17
arcminutes (approximatelly 40 to 40 pc).
(Park et al. Chandra data) astro-ph/0311460
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A closer look
Chandra. 2-10 keV
2.4 pc
20 pc
1007.4174
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Stellar dynamics around Sgr A
With high precision we know stellar dynamics
inside the central arcsecond (astro-ph/0306214)
The BH mass estimate is 4 106 ?0
It would be great to discover radio pulsars
around Sgr A (astro-ph/0309744).
(APOD A. Eckart R. Genzel )
Stars-star interactions can be important arXiv
0911.4718
One of the latest data 0810.4674
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Observations aboard Integral
At present our black hole is not
active. However, it was not so in the past.
It is suspected that about 350 years ago Sgr A
was in a high state. Now the hard emission
generated by Sgr Aat this time reached Sgr
B2.Sgr B2 is visible due to fluorescence of iron.
(Revnivtsev et al.)
About high energy observations of thegalactic
center see the review astro-ph/0511221and .
The galactic center region is regularly
monitoredby Integral.
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New Integral data
1007.4174
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Sgr A and H.E.S.S.
See astro-ph/0503354, 0709.3729
Still, resolution is not good enoughto exclude
the contribution of somenear-by (to Sgr A)
sources.
(Aharonian et al. 2005)
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X-ray bursts from Sgr A
Bursts can happen about once in a day. The flux
is increased by a factor of a few (sometimes even
stronger). A bright burst was observed on Oct.
3, 2002 (D. Porquet et al. astro-ph/0307110). Dur
ation 2.7 ksec. The fluxed increased by a
factor 160. Luminosity 3.6 1035 erg/s.
In one of the bursts, on Aug. 31,2004,QPOs have
been discovered. The characteristic time 22.2
minutes (astro-ph/0604337). In the framework of a
simple modelthis means that a0.22.
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X-ray vs. TeV
Simultaneous burst observationsby Chandra and
H.E.S.S. The flare is not visible at the TeV
range
0812.3762
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IR burst of Sgr A
Observations on Keck, VLT. The scale of
variability wasabout 30 minutes. This is similar
to variabilityobserved in X-rays. The flux
changed by a factor 2-5. Non-thermal synchrotron?
(Feng Yuan, Eliot Quataert, Ramesh Narayan
astro-ph/0401429)
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Constraints on the size of Sgr A
Using VLBI observations a very strict limit was
obtained for the sizeof the source Sgr A 1.
a.e.
astro-ph/0512515
New VLBI observations demonstrate variability at
1.3mm from the regionabout few Schwarzschild
radii. arXiv 1011.2472
Strict limits on the size and luminosity with
known accretion rateprovides arguments in favor
of BH interpretation (arXiv 0903.1105)
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Bubbles in the center of the Galaxy
Structures have been already detected in
microwaves (WMAP) and in soft X-rays (ROSAT)
arXiv 1005.5480
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M31
Probably, thanks toobservations on Chandra and
HST the central SMBHwas discovered in
M31(astro-ph/0412350). M(1-2) 108 Msolar Lx
1036 erg/s
See recent data inarXiv 0907.4977
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A large BH in M31
0907.4977
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Activity of the M31 SMBH
SMBH with 100-200 solar masses. Mostly in the
quiescent state. Luminosity is biilions of
timesless than the Eddington. Recently, bursts
similar to theactivity of Sgr A have been
detected from the SMBH in M31.
arXiv 1011.1224
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Active galactic nuclei and quasars
The classification is not very clear

• Quasars
• a) radio quiet (two types are distinguished)
  b) radio loud c) OVV (Optically Violently
  Variable)
• Active galaxies a) Seyfert galaxies (types 1
  and 2) b) radio galaxies
• c) LINERs d) BL Lac objects

• Radio quiet
• a) radio quiet quasars, i.e. QSO (types 1 and
  2) b) Seyfert galaxies c) LINERs
• Radio loud a) quasars b) radio galaxies
  c) blazars (BL Lacs ? OVV)

(see, for example, astro-ph/0312545) A popular
review can be found in arXiv 0906.2119
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Quasars spectra
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Spectra of BL Lacs
In the framework of the unifiedmodel BL Lacs
(and blazars,in general) are explained asAGNs
with jets pointingtowards us.
Ghisellini (1998)
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Active galactic nuclei blazars
EGRET detected 66 blazars 4 6 FSRGs 1 7 BL
Lacs Many blazars have been detected only
during outbursts. It is important to monitor
gamma-rayactivity of blazars, especially
afterGLAST will increase their number (gt1000).
MeV blazars Break in the spectra at 1-30 MeV
(Sikora et al. astro-ph/0205527)
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Outbursts of blazars
3C 454.3 Data not in X-rays and UVhave been
observed not simultaneously. Solid and dashed
linesare both SSC model. Flux at the range1-30
MeV is equal to 10-10 erg/cm2/s. Variability on
the time scale of several days.
(Giommi et al. astro-ph/0606319)
25
AGILE observations of 3C 454.3
1102.4428
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AGILE observations of PKS 1510-089
ECD External compton on disc rad. ECC- External
compton on BLR rad.
1102.4428
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Fermi observations of blazarsHuge set of data
0912.2040
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Blazar sequence
Fermi dataSpectral index in gamma-raysvs.
gamma-ray luminosity
1001.4015
29
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1211.1671
30
Unified model
In the framework of the unified modelproperties
of different types of AGNsare explained by
properties of a torusaround a BH and its
orientationwith respect to the line of sight.
Antonucci 1993 ARAA 31, 473
31
Unified model and population synthesis
X-ray background is dominated by AGNs. Discussion
of the nature and properties of the background
resultedin population synthesis studies of AGNs.
Ueda et al. astro-ph/0308140 Franceschini et
al. astro-ph/0205529 Ballantyne et al.
astro-ph/0609002
What should be taken into account

• Relative fracton of nuclei obscured by toruses
• Luminosity distribution of nuclei
• Spectral energy distribution
• Evolution of all these parameters

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Mass determination in the case of SMBHs

• Relation between a BH mass and a bulge mass
  (velocity dispersion).
• Measurements of orbits of stars and masers
  around a BH.
• Gas kinematics.
• Stellar density profile.
• Reverberation mapping.

Also, always a simple upper limit can be put
based on the fact that the total luminosity
cannot be higher than the Eddington value.
See a short review by Vestergaard in
astro-ph/0401436 Black-Hole Mass
Measurements See a recent review in
0904.2615,and 1001.3675
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Different methods
1001.3675
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Comparison
1001.3675
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BH mass vs. bulge mass
According to the standard picture every galaxy
with a significant bulge hasa SMBH in the center.
MBH Mbulge 1.12/-0.06 (Haering, Rix
astro-ph/0402376) BH mass usually is about
from 0.1 up to several tenth of percent of the
bulge mass.
(www.mpia.de)
36
Exceptions ?33
The upper limit on the BH massin M33 is an order
of magnitudelower than it should beaccording to
the standard relation.
(Combes astro-ph/0505463)
37
New data
1007.3834
38
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XMM-Newton ????????,??? ? ??? ???? ????????
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????? ?????? ???? gt20000 MO
1209.1354
39
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????? ?????? ???? 108 ??? ???????????? gt1010 MO!
1211.6429
40
Omega Centauri cluster
(arXiv 0801.2782)
Supported by arXiv 1002.5037
41
Alternative results on Omega Centauri
MBH lt 18 000 solar (3 sigma) Results by Noyola et
al. (2008) are strongly criticized. Probable IMBH
with 8000 solar, but within 3 sigma it is
possible to have no BH at all.
arXiv0905.0627
42
New measurements
VLT-FLAMES data in the very central
part. Different panels are plotted for different
positions of the cluster center. Different curves
correspond to different BH masses 0, 1, 2, 3, 4,
5, 6, 7.5 (in tens thousand solar masses).
1007.4559
43
There are other correlations
In the figure the following correlationis shown
absolute magnitude of the bulge (in V filter)
vs. BH mass. BH masses are obtained by
reverberation mapping. Other correlations are
discussedin the literature.
(Wu, Han AA 380, 31-39, 2001)
44
Fundamental plane
The correlation between effective size, surface
brightness andvelocity dispersion in giant
elliptical galaxies.
into the upper relation
Lets substitute
then we have
(Faber-Jackson relation)
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Supermassive black holes do not correlate with
galaxy disks or pseudobulges
1101.3781
See also arXiv 1012.0834 about SMBH massesin
bulgeless galaxies
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Supermassive black holes do not correlate with
dark matter halos of galaxies
Based on data for bulgeless galaxies.
Also bulgeless
1101.4650
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Masers
Observing movements of masers in NGC 4258 it
became possible to determine the massinside 0.2
pc. The obtained value is 35-40 million solar
masses. This is the most precise method ofmass
determination.
NGC 4258. Miyoshi et al. (1995)
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Several new megamaser measurements
Circles new measurements,stars from the
literature.
1007.2851
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Gas kinematics
For ?87 gas velocities were measure inside one
milliarcsecond (5pc). The mass is 3 109 M0. It
is one of the heaviest BHs.
(Macchetto et al. astro-ph/9706252)
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Masses determined by gas kinematics
Masses determinedby observing gaskinematics are
ingood correspondencewith value obtained by
reverberation mapping technique.
ArXiv 0707.0611
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Mass via hot gas observations
Giant elliptical galaxy NGC4649. Chandra
observations. Temperature peaks at 1.1keV within
the innermost 200pc. Under the assumption of
hydrostatic equilibrium it is demonstrate that
the central temperature spike arises due to the
gravitational influence of a quiescent central
super-massive black hole.
arXiv 0801.3461
52
Stellar density profiles
(Combes astro-ph/0505463)
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Reverberation mapping
The method is based on measuring the response of
irradiated gas to changesin the luminosity of a
central sources emitting is continuum. Initially,
the method was proposed and used to study novae
and SN Ia. In the field of AGN was used for the
first time in 1972 (Bahcall et al.) An important
early paper Blandford, McKee 1982.
What is measured is the delay between changes in
the light curve in continuumand in spectral
lines. From this delay the size of BLR is
determined.To apply this method it is necessary
to monitor a source.
dimensionless factor,depending on the geometry
of BLRand kinematics in BLR
clouds velocities in BLR
The method is not good for very bright and very
weak AGNs.
( For details see arxiv0705.1722)
See a detailed recent example in 1104.4794
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Correlation size - luminosity
(Kaspi arxiv0705.1722)
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Scaling from X-ray BH binaries
1104.3146
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Disc size BH mass
Disc size can bedetermined frommicrolensing.
arXiv0707.0305 Christopher W. Morgan et al. The
Quasar Accretion Disk Size - Black Hole Mass
Relation
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New data
IR and optics
1007.1665
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r1/2?4/3
1007.1665
59
1007.1665
60
1007.1665
61
1104.2356
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Masses in QSOs for different z
1104.1828
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Alternatives to BHs
With all wealth of choices there is no other
alternative (c) Supermassive black holes- is the
most conservative hypothesis. Discussions of
not-so-exotic alternatives (cluster of low-mass
stars, stellarremnants, etc.) as well as
moderately exotic scenarios (exotic objects
orclusters of weakly interacting particles in
the presence of normal stellar mass BHs)result
in the conclusion that for all well studied
galaxies (for example, M31, M32)a BH formation
is inevitable (astro-ph/0512194). (About some
exotic alternatives well also speak in the last
lecture)