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Charleston SC 18 October 2011; JPO. Momentum Driving in AGN and Galactic Feedback. Co-conspirators*: E. Choi L. Ciotti P. Johansson T. Naab G. Novak D. Proga S.Y.Sazonov R.A.Sunyaev. Cartoon of Co-Evolution of Elliptical and MBH/AGN.

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momentum driving in agn and galactic feedback

Charleston SC

18 October 2011; JPO

Momentum Driving in AGN and Galactic Feedback


E. Choi

L. Ciotti

P. Johansson

T. Naab

G. Novak

D. Proga



cartoon of co evolution of elliptical and mbh agn
Cartoon of Co-Evolution of Elliptical and MBH/AGN
  • 1) Black holes postulated in the 1960s to explain rare events in distant galaxies - huge EM output from small sources.
  • 2) Now we know that ALL massive galaxies, near and far, contain MBH’s and that most are in the “off” state, ie small duty cycle.
  • 3) But modern treatments almost all ignore the radiative output!
  • 4) Biggest source of mass to feed MBH is recyled gas from stellar evolution - typically ignored.
prologue historical
Prologue - Historical
  • 1) Black holes postulated in the 1960s (DLB) to explain rare events in distant galaxies - huge EM output from small sources. And BAL winds. But modern treatments typically ignore these outputs!
  • 2) Now we know that ALL massive galaxies, near and far, contain MBH’s and that most are in the “off” state, ie small duty cycle.
  • 3) Biggest certain source of mass to feed MBH is recyled gas from stellar evolution - typically ignored.
  • 4) Winds and radiation from AGN (“feedback”), must affect galaxy and growth of BH. Which processes are most important?
agns and starbursts physical processes consequent to normal galactic evolution
AGNs and Starbursts: physical processesconsequent to normal galactic evolution
  • Co-incident and co-terminous: gas added to the center of galaxies feeds central black hole AND also fuels starburst. Processes comparable in importance.
  • Gas added via mergers probably not dominant at low redshift.
  • Gas source from recycled gas is 25% of stellar mass; galactic merger induced gaseous in-fall may be comparable but less, especially at late times (z < 1.5).
  • Energy and momentum input due to
    • Radiative input: UV from stars, and UV-Xray from AGN
    • Mechanical: BAL winds & SN from stars
mergers of relatively low importance
Mergers of relatively low importance:

One of many recent papers on this topic….

Title: The clustering of narrow-line AGN in the local Universe

Authors: Cheng Li, Guinevere Kauffmann, Lan Wang, Simon D.M. White, Timothy M.

Heckman, Y.P. Jing

Comments: 14 pages, 11 figures, submitted to MNRAS


We have analyzed the clustering of ~ 90,000 narrow-line AGN drawn from the

Data Release 4 (DR4) of the SDSS. We compute the cross-correlation between AGN

and a reference sample of galaxies, and compare this to results for control

samples of inactive galaxies matched simultaneously in redshift,stellar

mass,concentration, velocity dispersion and the 4000A break strength. We also

compare near-neighbour counts around AGN and around the control galaxies. On

scales larger than a few Mpc, AGN have almost the same clustering amplitude as

the control sample. This demonstrates that AGN host galaxies and inactive

galaxies populate dark matter halos of similar mass.On scales between 100kpc

and 1Mpc,AGN are clustered more weakly than the control galaxies. We use mock

catalogues constructed from high-resolution N-body simulations to interpret

this anti-bias, showing that the observed effect is easily understood if AGN

are preferentially located at the centres of their dark matter halos. On scales

less than 70 kpc, AGN cluster marginally more strongly than the control sample,

but the effect is weak. When compared to the control sample, we find that only

one in a hundred AGN has an extra neighbour within a radius of 70 kpc. This

excess increases as a function of the accretion rate onto the black hole, but

it does not rise above the few percent level. Although interactions between

galaxies may be responsible for triggering nuclear activity in a minority of

nearby AGN, some other mechanism is required to explain the activity seen in

the majority of the objects in our sample.

agn output in units of stellar mass x c 2
AGN output in units of stellar mass x c2
  • Multiply efficiency by rBH = MBH/M* = 0.0013
    • EM,AGN = 0.12 x 0.0013 = 1.6 x 10-4
    • UV,AGN = EM x 0.2 = 3.2 x 10-5
    • mech,AGN= 0.005 x 0.0013 (BAL) = 5.2 x 10-6

BAL Dominates because coupling is most efficient

momentum driving
Momentum Driving
  • (dM/dt)acc = (dM/dt)inf -(dM/dt)out
  • dE/dt = ½ v2(dM/dt)out = mech (dM/dt)acc c2
  • Ψ = (dM/dt)out/ (dM/dt)acc = 2 mech c2/v2

= 9/v102For standard mech

  • dp/dt = v (dM/dt)infΨ /(1+Ψ )

Ψ > 0 changes the game.

sequence of problems to be solved
Sequence of problems to be solved:
  • 1) Embed MBH in a typical elliptical galaxy to compute winds, duty cycle and limiting growth of MBH.
  • 2) Allow for star-formation in regions of dense cold gas to estimate properties and recurrence of starbursts.
  • 3) Add dust, radiation pressure on the dust, a central disk, with star-formation and wind from AGN + disk.
  • 4) Add mechanical energy and momentum input from AGN wind.
  • 5) Proceed: 1D -> 2D -> 3D
physics included and excluded in typical bh accretion calc s
Physics included and excludedin typical BH accretion calc’s
  • Included:
    • Dynamics: gravity and hydrodynamics.
    • Atomic physics: cooling, electron-ion coupling etc.
    • Radiative emission processes.
  • Sometimes included:
    • Feedback from accretion to the region of the central engine.
    • Viscous effects, MHD.
  • Not included (usually):
    • Momentum from outflowing winds; a big effect.
    • Shocks, shock heating & cosmic ray generation.
    • Radiative heating due to luminosity of interior material.

This omission is strange, given the enormous observed hard X-ray luminosities of accreting black holes !


Conclusion: most energy emitted in UV, but weighted by photon energy it is in the X-Ray region

Observational determination of the mean AGN emitted spectrum from individual objects and the X-Ray-background.


Most work presented at this conference has taken as GIVEN the inflow to the central black hole. Understanding this “outer boundary condition” is critical to understanding the feedback/AGN wind problem. In all of the work that I will be describing a the Bondi radius is resolved and no assumption of Bondi flow is needed. The hydro code itself decides how much matter flows towards the central black hole.


Compton Temp and Radiative Heating

= 2 107 K

Independent of Optical/UV absorption and of direction (for isotropic initial emission).

Elementary Thermodynamics: kTgas -> <h> ~ kTC

accretion of mbh within elliptical galaxy w l ciotti
Accretion of MBH within elliptical galaxy (w L. Ciotti)
  • Detailed spherically, symmetric, time-dependent hydro of accreting MBH in E galaxy with
  • Assumed accretion efficiency (0.001 -> 0.100).
  • Assumed Spectrum with Tcompt = 107.5->109.0.
  • -------------------------------------------------------------------------------------
  • Relaxation oscillations: cooling, infall, photo-heating, expanding hot bubble, cooling….
  • Most time in non-accreting state (fduty ~ 0.006), galaxy looks like normal elliptical.
  • In burst mode looks like a quasar.
  • Final MBH masses reasonable.
  • Elliptical gas luminosity reasonable.

Thermal gas radiation

10 40 ≤LX,gas ≤ 1042

“Cooling flows”

repeat with allowance for starburst feedback from both agn and stars
Repeat with allowance for starburst; feedback from both AGN and stars.
  • Accurate stellar dynamical model (separate Hernquist profiles for DM and stars). Orbits evolved as mass profile changes.M87 type gal.
  • Accurate stellar evolution (Renzini) for mass loss in PN, red-giant winds, SN etc. Gives mass, energy and metals input vs time.
  • Star-formation via conventional formalism from cold collapsing regions. Gives additional (M,E,Z).
  • AGN radiative feedback with detailed atomic phys.

Energy Input Rates from MBH, old stars and gas

Red: MBH

Green: Old stars

Black: Gas emission

Note: “quiet” level now computed by high resolution code. Not “sub-Bondi”.


Mass flow rates from recycled gas, to MBH and wind

Recycled gas from planetary nebulae.

Galactic wind into ambient medium driven by AGN bursts with peak value at 100 Msolar/yr.


Luminosity Distribution as Observed

“Cooling flow” model

overall results
Overall Results
  • Lx, gas in right range.
  • MBH appropriate (not too large).
  • Modest mass outflow driven by momentum
    • BAL wind input
    • and radiation on dust the biggest drivers
  • Duty cycle ~ 0.006.
  • -------------------------------------------------
  • Appears most times as a normal elliptical, some time as an incipient cooling flow and during very brief intervals as a quasar.
add nuclear disk dust and radiation pressure on the dust
Add nuclear disk, dust and radiation pressure on the dust
  • Innermost shell dumps gas onto gaseous disk, within which stars form a la Schmidt law with bulk going to wind and central BH in observed ratios.
  • Radiation pressure from newly formed stars in central regions (disk + nuclear starburst) allowed to act on inflowing dusty cold gas dominates over gas pressure and Eddington effects during star-bursts.
nuclear region a stars outlast the bursts e a spectrum
Nuclear region A stars outlast the bursts -> “E + A” Spectrum

Optical starburst

red: BH (solid= Eddington; dotted=accretion lum., dashed = absorbed)

green: STARS (solid = LsnIa; dotted = LsnII; dashed = thermalization of stell. mass losses)

green: STARS (dot-dashed=optical starburst; long-dashed = UV starburst)

black: ISM (solid = X-ray, dotted = bolometric)

very low final gas fraction
Very low final gas fraction

At late times the gas mass in the galaxy is less than the ejected and consumed mass

TOP: solid = total BH accreted mass; dotted = ISM mass in the galaxy

BOTTOM: same as above, but for rates; dashed: mass loss rate from the galaxy as a wind

agn wind produces snr like conical cavity after outburst
AGN Wind Produces SNR Like Conical Cavity after Outburst
  • Wind velocity similar to SNR outburst velocity.
  • Surrounding medium of similar density.
  • Boundary shock and Sedov like propagation of cavity.
  • Shock acceleration of relativistic particles at at the interface.
  • Inevitable production of non-thermal synchrotron radiation.
brief non thermal phase after an outburst and cr generation a giant snr
Brief Non-Thermal Phase after an Outburst and CR Generation: A giant SNR!

Y.-F. Jiang, L. Ciotti & JPO (2009)

efforts towards 2 d solution proga o 2008
Efforts towards 2-D Solution (Proga&O,2008)
  • Wind produced with Mdot,w >~ Mdot,acc
  • Small solid angle until Edd Luminosity approached.
  • Energy efficiency ~ 1 x 10-4
  • Cold cloud ejection at high Eddington rates.

No Rotation Rotation

Vel & Density



No X-ray Heating X-ray Heating

Higher density at outer boundary (x 10)


Possibility of background X-ray heating

details of large scale 2 d sims
Details of Large Scale 2-D Sims
  • Same physics as 1-D including both the radiative and mechanical effects and allowing for all momentum fluxes as drivers.
  • Done with Greg Novak (Princeton) using the ZEUS (J.Stone) code.
  • Logarithmic scale from 2.5 pc (inside Rbondi) to 250kpc in increments of dR/R of 10%.
  • Gas ejection into polar cone w velocity 10,000 km/s
  • Accretion not “assumed at Bondi rate” or by any other formula but computed by standard hydrodynamical means with infall inner BC.

Bursting more irregular than in 1-D case, infalling shells fragment via R-T instability.


Heckman et al, 613,109 (2004)

Greene & Ho, 637,131 (2007)

Ho, 699,626 (2009)




After the party

zoom out effects on ambient medium
Zoom Out – Effects on Ambient Medium

Two-D hydrodynamic simulation (Novak & JPO; 2009) cf Fabian (2009)


3-D treatment (E.Choi, P. Johansson, T. Naab &JPO):

H&S + mass and momentum + radiation +B limit

Add Bondi Criterion

Add Radiation Feedback

Higher fluctuation rate and slower accretion

Lower accretion rate


Thermal FB vs Momentum + Radiation

Oscillation between low and high Eddington ratios

3 d work
3-D Work
  • BH growth is regulated similar to S&H
  • Bursting phenomenon preserved from 1-D and 2-D results.
  • High velocity wind similar to BAL is generated.
  • At same energy efficiency, momentum driving is far more effective than thermal input (38% vs < 1%).
  • Feedback must be important. Both mechanical and radiative feedback regulate the growth of massive black holes. Magorrianrelation. Duty cycle <~ 1%.
  • Re-cycled gas from late stellar mass loss (25%) must produce outbursts. Star-formation, SNII and AGN feedback use up and drive gas out of the nucleus.
  • Momentum input from central winds is the dominant driver.
    • Radiative momentum from optically thick dust (Quataert et al); important.
    • Winds from broad-line outflows; dominant.
primary predictions
Primary Predictions
  • Low duty cycle outbursts expected with coupled AGN and starburst effects in normal ellipticals from recycled gas. Metal rich outflows.
  • Longer timescale (~ cooling time) low density high temperature central bubbles should be observable.
  • Radioactivity likely from particle acceleration in the outgoing shocks -> synchrotron emission, eg like SNR.
  • Stellar population of central regions of elliptical galaxies should be red (metal rich) and relatively young. “ E +A star” spectra will survive the nuclear starburst as evidence.
  • Weak shocks propagate into surrounding IGM as crescent like enhancement.