Outbursts from Supermassive Black Holes
Forman, Churazov, Jones, Bohringer, Begelman, Owen,
Eilek, Nulsen, Vihlinin, Markevitch, Heinz, Kraft
M87 interaction between a SMBH and gas rich atmosphere
Shocks, Buoyant plasma bubbles, Jet, Cavities, Filaments
Unambiguous signature of an AGN triggered shock
Outburst energy
Outburst duration
Energy channels for heating
Cool X-ray filamentary structure
Clear evidence for bubbles
•Outbursts from galaxies to (M87 to) rich clusters
•Outbursts range from 1055 < ∆E < 1062 ergs
•See growth of SMBHs - ∆MSMBH ∆ EOUTBURST / c2
•∆MSMBH up to 3x108 solar masses per outburst
SMBH and Parent Galaxy
M
M
Mbulge-M
M - 
Magorrian et al.
Gebhart et al.
Ferrarese & Merritt
Velocity Dispersion
MBulge
Hot X-ray emitting atmospheres - “fossil record” of SMBM activity
•Observe outburst frequency
•Measure total power - mechanical vs. radiative (cavities)
•Understand interaction of outburst with surroundings
•Insight into high redshift, early universe
•Growth/formation of galaxies
•Growth of SMBH
2
Millenium Run + Semi-analytic Galaxy Evolution
Croton et al. 2006
•1010 particles of 109 Msun
• extract merger trees of dark matter
halos from z=20 to z=0
•z=0 dark matter
•z=0 light
Croton et al. 2006
“The many lives of active
galactic nuclei: cooling
flows, black holes and the
luminosities and colours
of galaxies”
3
Millenium Run + Semi-analytic Galaxy Evolution
Croton et al. 2006
For massive
galaxies/halos, AGN
feedback into hot
coronae is long-lived
phase
Rapid
Cooling
Hot Halo
Study this long-lived
phase of outbursts and
feedback into the hot
coronae
Massive halos/galaxies
•Form hot gas coronae at early times
•Growth/merging continues with little star formation
•Oldest systems become “red and dead” - but still growing via mergers
•AGN heating is key
•Downsizing - more massive galaxies end star formation at higher z;
appears “anti-hierarchical”
4
Setting the stage
Family of increasing mass, temperature, and luminosity
E/S0 Galaxies
Groups
Clusters
Lx (ergs/sec)
1040-42
1042-43
1043-46
Gas Temp
0.5-1.0 keV
1-3 keV
2-15 keV
Mgas/Mstellar
0.02
1
5
5
Setting the stage
Family of increasing mass, temperature, and luminosity
Hot gas seen ONLY in X-ray band - thermal bremsstrahlung + lines
•Gas provides a fossil record of mass ejections and energy outbursts
•For clusters, 16% of mass is luminous baryons (mostly hot gas)
•Measure heavy element enrichment - history of star formation
•See reflections of energy outbursts in cavities over cosmic times
6
Cooling
Flows
Allen/Fabian
•
Cowie & Binney (1977) Fabian & Nulsen (1977) “Cooling gas in the cores of clusters
can accrete at significant rates onto slow-moving central galaxies”
•
Strong surface brightness peak  dense gas  short cooling time
•
Hot gas radiates – gas must cool unless reheated, then compressed by ICM
•
Mass Deposition rates are large (100 -1000 M/yr) - more than 50%
•
But large amounts of cool gas were not detected
•
Emission lines from cooling gas NOT SEEN byXMM-NEWTON OGS (cool gas only
10% of prediction) (e.g., Peterson et al. 2001, 2002; Peterson & Fabian 2005)
7
Virgo Cluster - X-ray/Optical
1’=4.65 kpc; 2o=0.5 Mpc
Central galaxy in Virgo cluster
D=16 Mpc
•3x109Msun supermassive black hole
•Spectacular jet (e.g. Marshall et al.)
•Nearby (16 Mpc; 1’=4.5 kpc, 1”=75 pc)
•Classic cooling flow (24 Msun/yr)
•Ideal system to study SMBH/gas interaction
Chandra-XMM-VLA View
•
•
•
Two X-ray “arms”
X-ray (thermal gas) and radio (relativistic plasma)
“related”
Eastern arm - classical buoyant bubble with torus
(Churazov et al 2001)
– XMM-Newton shows cool arms of uplifted gas (Belsole
et al 2001; Molendi 2002)
•
Southwestern arm - less direct relationship - radio
envelops gas
M87
Chandra-XMM-VLA View
M87
Churazov et al. 2001
Gas Pressure (3.5-7.5 keV)
Gas Density (1.2-2.5keV)
Density and Pressure Maps
Central Piston
Shock
Filamentary arms
Schematic
Shock
ICM
Bubble
ICM
12
Central Region of M87 - the driving force
SMBH 3x109Msun
6cm VLA
•
•
•
Nucleus, jet (knots)
Cavities surrounding the jet and the (unseen)
counterjet
Bubble breaking from counter jet cavity
– Perpendicular to jet axis;
– Radius ~1kpc.
– Formation time ~4 x106 years
• Piston driving shock
• X-ray rim is low entropy gas
uplifted/displaced by relativistic plasma
6 cm
Shock Model I - the data
Hard (3.5-7.5 keV) pressure
soft (1.2-2.5 keV) density profiles
Projected
Deprojected
Deprojected Gas Temperature
Shock
Rarefaction
No hot shocked region interior to shock
Consistent density and temperature jumps
Rankine-Hugoniot Shock Jump Conditions
  1M 2

 2 / 1 =
  1   1M 2 1
2 / 1 =1.34
  1  2 M
T /T =
2

1
2


1   1   1M 2 1
  1
2
M2
T2/T1= 1.19
yield same Mach number:
(MT=1.20  =1.24)
M~1.2
Outburst Energy
Series of models with varying
initial outburst energy
2, 5, 10, 20 x 1057 ergs
Match to data
E = 5 x 10 57 ergs
Determined by jumps
Derive outburst timescale
Fast - large shock heated
region
Absence sets outburst
duration 2-5 million yrs
Slow - cool rim
Shock-heated gas if
outburst is too short
Absence of hot region limits duration of outburst
Must be longer than 2 million years
Fast
Hot, dim
Fast/Slow
Cartoon
Radio
Fast
Slow
Small
Large
Yes
No
Cool rims
No
Yes
Rarefaction region
Yes
Yes
Outer shock
Yes
Yes
Lobes
Radio Lobes
Radio bright
X-ray dim
Shock heated gas
Radio dim
Cool, bright
Radio
Lobes
X-ray dim
Slow
19
Where does the energy go ?
Sedov
Slow (2-5 Myr)
Kinetic energy ~6x1056 ergs
in the shock
(11%)
~6x1056 ergs
(11%)
Will be carried ~12x1056 ergs
away
(22%)
~12x1056 ergs
(22%)
~2.3-3.7x1057 ergs
(46%-64%)
Enthalpy of
the central
bubble
Heating
~1.7x1056 ergs
(3.4%)
100-22=78%
>100-22=78%
(eventually)
20
Soft Filamentary Web
90 cm (Owen et al.)
M87
4.65 kpc
Sequence of buoyant bubbles
Many small bubbles (comparable to “bud”)
Effervecent heating - Begelman
•PV ~ 1054 - 1055 ergs
rise ~ 107 years
Arms - resolved
Eastern arm - classical buoyant bubble
Southwestern arm - overpressured and “fine”
(~100pc, like bubble rims) - limit bulk gas
velocities in core
1.2-2.5 keV
Organized and Disorganized
QuickTime™ and a
YUV420 codec decompressor
are needed to see this picture.
QuickTime™ and a
YUV420 codec decompressor
are needed to see this picture.
Ruszkowski/Begelman
Simulation for Perseus
Both large scale bubbles
AND
Small scale chaotic bubbles
4.65 kpc
22
M87 shocks and bubbles contribute to heating
Both naturally arise from AGN outbursts
Radio (blue) Chandra X-ray (red)
Shock carries away ≤ 20-25% of energy
75% of outburst available to heat (eventually)
Filaments
Cool thermal rims of bubbles
Southwestern arm - interaction with radio plasma
Shock (and trailing rarefaction region)
R, jump in T or ρ => Total deposited energy 5x1057 erg
Lobes and shock radius => Age ≈ 14x106 yr
Cool/bright rims => “slow” energy deposition 2-5x106 years
Average energy release: few x 1043 erg/s ≈ Cooling losses
Dunn et al. - 55 cluster sample, 20 have <3x109 yrs and 75% show bubbles
Rafferty - 33 clusters; 50% withbubbles and sufficient energy to quench
cooling
Hot Gas in Early-type Galaxies - The Einstein Era
Pre-Einstein early type galaxies
•Gas free - Stellar mass loss removed by SN driven winds.
Einstein Observatory images showed extended, hot coronae:
•~1 keV temperatures; masses to 1010 M ,
•Strong correlation of LX and LB but much scatter.
(e.g. Forman et al. 1979, 1985, Canizares et al. 1987)
•High central gas densities => short cooling times
•Accretion rates of 0.02-3 Msun/year (Nulsen et al. 1984, Thomas et al.
1986 )
A Chandra survey of ~160 early type galaxies to measure
outburst energy, age, frequency, plus diffuse/gas luminosity
and nuclear emission (Jones et al.)
Study hot gas - as a function M, velocity dispersion, ….
Measure cavities - determine outburst energies (PV) and timescales
Derive nuclear luminosities - correlate with gas density
Chandra resolution required!
In luminous ellipticals, most of the X-ray emission is from hot gas,
In fainter systems, emission from LMXBs makes nearly all of the
“diffuse” emission
Gas dominates “diffuse” emission
Correlation of Lx with L
and Land 
Galaxies with little hot ISM
Mostly unresolved LMXB’s
(hard specta)
Exploding Elliptical -NGC4636
Jones et al 2001
•Strange X-ray structure in an otherwise normal Virgo elliptical galaxy
•Double pin wheel-like structure in X-rays! X-ray arms ~8 kpc long.
•Nuclear outburst 3 x 106 years ago with energy 6 x 1056 ergs
•But small weak radio source
Bubbles in a galaxy -- M84
X-ray
Radio
Lobes ~ 4 kpc diameter
outburst ~ 4 - 6 x 106 yrs ago
Interaction with radio lobes of 3C272.1
Tail to south & northern lobe compression
.
motion of M84 to the north
For Perseus, M87,
M84, and for almost
all others
Gas surrounding
bubble is cool
Usually no shock
heating in lobe
H-shaped gas has
kT~ 0.6 keV
Ambient gas
temperature increases
from 0.6 to 0.8 keV
with increasing radius
29
Galaxy rims are (generally) cool (like cluster) - no shocks
Bubbles (seen as cavities) gently uplift and impart energy to the gas
NGC4636
2 106 years
3 106 years
5 106 years
3 106 years
NGC5846
NGC507
107 years
107
5
years
5 106 years
How Common are AGN Outbursts in Galaxies?
Determine fraction of Galaxies with Cavities
Galaxies with diffuse gas
Galaxies with cavities
In luminous ellipticals (including some poor groups), 30% have cavities
In galaxies, outbursts are recent (=> frequent) and
impart significant energy to the ISM
AGE of outbursts
1053
1055
1057
1059
PV (ergs)
Ages and outburst energy for the 27 systems with cavities
Nuclear activity - “AGN”
Determine fraction with nuclear X-ray emission
In “normal” early-type
galaxies
•X-ray emission detected
from the nucleus for
~80% of early-type
galaxies
Conclusions
Energy input from AGN is common in galaxies
- reheats cooling gas, drives gas from their halos,
and is important for galaxy evolution
In luminous ellipticals, ~30% have cavities => recent
outbursts
- typical ages are 3x106 to 6x107 years
- typical outburst energies (estimated from cavity sizes)
are 1055 - 1058 ergs
~80% of all early type galaxies have weak X-ray “AGN”
Hydra A (Nulsen et al 2005)
Small cavities in core, medium cavities and a shock
Shock front 200-300 kpc from AGN
Shock energy 1061 ergs -- 1.4 X 108 years since outburst 35
Hydra A (Nulsen et al 2005)
Chandra
radio contours on X-ray
Small cavities in core , medium cavities and a shock
Shock front 200-300 kpc from AGN
Shock energy 1061 ergs -- 1.4 X 108 years since outburst
Cluster Scale Outbursts
MSO735.6+7421 6 X 1061 ergs driving shock
(McNamara et al 2005)
Cluster Lx = 1045 ergs/sec z=0.22
X-ray bright region - edge of radio cocoon lies at location of shock
Radio lobes fill cavities (200 kpc diam) - displace and compress X-ray gas
Work to inflate each cavity ~1061 ergs; age of shock 1 X 108 years
Average power 1.7 X 1046 ergs/sec
Outbursts from Clusters to Galaxies
SOURCE
MS0735.6
Hercules A
Hydra A
M87
NGC4636
SHOCK
RADIUS
(kpc)
ENERGY
230
160
210
14
5
5.7
3
0.9
0.0005
0.00006
(1061 erg)
AGE
∆M
(My)
MEAN
POWER
(1046 erg/s)
(108 Msun)
104
59
136
14
3
1.7
1.6
0.2
0.0012
0.0007
3
1.7
0.5
0.0003
0.00003
Growth of SMBH by accretion in “old” stellar population systems
(Rafferty et al. 2006 - MÝBH  0.11 solar mass/yr)
with star formation to maintain MBH-Mbulge relation
Mechanical power balances cooling in 50% of clusters
AGN outbursts deposit energy into gas through shocks and bubbles

Impact of AGN outbursts on hot gas
•M87 outburst ~14x106 years, ~2-5x106 years; inflates inner region
“classical shock - seen in density/temperature & rarefaction region
slow expansion of “piston” (no large shock heated region)
Outburst energy matches cooling
• M87 arms from buoyant bubbles; soft filamentary web; complex (magnetic
field) interactions of radio plasma bubbles with ISM
•Galaxy outbursts and mini AGN are common (see talk by Christine Jones)
•Outbursts from galaxies to clusters 1055-1062 ergs which grow SMBH
Hydra A
M87
NGC4636
Impact of AGN outbursts on hot gas
•Reheat cooling gas through shocks/buoyant bubbles in all gas
rich systems i.e. those with bulges and black holes
•Critical to galaxy evolution/downsizing models
•Massive galaxies are “red and dead”
•Evolution continues but not (appreciable) star formation
•Hot coronae “contain” AGN feedback energy over
cosmological times
•X-ray observations allow study of the outbursts and exactly
how energy is injected into the hot surrounding atmosphere
•Critical to understanding the new view of galaxy and black
hole evolution
Hydra A
M87
NGC4636
41