Feedback Driven by Radio Sources

Brian McNamara

University of Waterloo

Baltimore, STScI May, 9 2012

Perimeter Institute for Theoretical PhysicsHarvard-Smithsonian Center for Astrophysics

Collaborators: P. Nulsen (CfA), H. Russell, CJ Ma, C. Kirkpatrick (Waterloo) M. Wise (Astron), K. Cavagnolo (Waterloo), A. Vikhlinin (CfA)

Mechanical Feedback in Radio AGN

Tucker, Tananbaum, Fabian 07, Scientific American

Radio-mechanical heating in X-ray atmospheres of galaxies, groups, & clusters

Evidence for actual feedback loop: cooling, star formation, AGN Consequences: quenching of cooling flows, red & dead phenomenon in ellipticals, color dichotomy in ellipticals

Recent developments: 1. Metal-enriched, large-scale outflows in clusters 2. AGN heating of hot atmospheres in distant clusters

Review:

Hot Atmospheres surrounding clusters and gEs

implies cooling flow: ne ~10-1 cm-3 M = 10-1000 M yr-1.X-ray luminosity 1044-45 erg s-1 exceeds radio synchrotron power 1040-42 erg s-1

Cooling flow problem: star formation ~ 1% M Problem in clusters and normal gEs

.

X-ray cooling cusp

NGC 1275 Perseus

T≈107-8 KZ=0.2-1 Z

thermal X-ray emission

A. Fabian

- Debris from stellar evolution- Heat & exhaust from SMBHs- Captured baryons

Hot atmospheres

Perseus

Chandra X-ray Observatory

MS0735

Hydra A

PerseusFabian et al. 2008

X-ray + radio = mechanical feedback

MS0735 McN + 05,09

Hydra A McN +00, Kirkpatrick+11

Credit: H. Russell

200 kpc1 arcmin

20 kpc

Mechanical AGN Feedback Regulates Cooling Chandra X-ray Observatory

cavities

McN+00

thermostatically controlled accretion

Radiative cooling = AGN heating of hot gas

==> feedback loop

-AGN mechanical power matched to cooling rates

-Short (<109 yr) cooling times in all systems

cooling gas

Key evidence:

Birzan+04, Rafferty+06, Dunn Fabian 06

Voigt & Fabian 04

heating

Hydra A

20 kpc

Measure: T, ne = Pth, EAGN = 1059 erg

“radio mode” feedback

Reviewed by McNamara & Nulsen 07 ARAA, McNamara & Nulsen 12, NJP, arXiv:1204.0006

pV

Nucleus

shock

cavity

accretion, spin

rnuc

• energy & age measured/estimated directly• measure mechanical (not synchrotron) power

1) Cavity enthalpy (pV work + internal energy)

Measuring Jet Power using X-ray Cavities

M ~1.2

McNamara + 00,01; Birzan + 04Churazov 01

Theory: Ruszkowski, Heinz, Bruggen, Begelman, Voit, Churazov, T. Jones, etc.

slow gas motions vg< cs,= gentle heating

Mechanical power dramatically exceeds radio power

Key breakthrough: even weak radio sources mechanically powerful enough power to regulate or quench cooling, X-ray atmospheres

radio

Radio Luminosity

Jet (

cavi

ty)

pow

er

cavityMcNamara & Nulsen 07 ARAA

Birzan + 04

Pjet > 1000 X Lradio

AGN heating balances cooling in gE’s & ClustersRafferty + 06 Birzan + 04 Dunn & Fabian 06

jet power

X-ray cooling luminosity

<heating> ≈ cooling

cooling, jet power are correlated over seven decades in jet power

heating knows about cooling: feedback

Rafferty +06, O’Dea +08Same process keeps ellipticals red & dead (Bower +06, Croton 06, Best +06)

See McNamara & Nulsen 12 for recent update

Voigt & Fabian 04

Conditions conducive to AGN Feedback Loop

Despite large AGN heating rates, central cooling times are short < GyrAGN heating and radiative cooling timescales are similar Conditions for feedback

Rafferty + 08

See Voit & Donahue 05, McNamara & Nulsen 07 ARAA, McNamara & Nulsen 12, NJP, arXiv:1204.0006

cooling time profiles tcool > tcav

cavity ageRadius (kpc)

coo

ling

tim

e (

109 y

r)

coo

ling

tim

e (

108 y

r)

Rafferty + 08

tc ≈ 108 yr

H

McNamara & Nulsen 12, NJP

O’Dea + 10

Residual cooling: UV emission from star formation in molecular-gas-rich BCGs

A1664 SFR ~ 20 Mo yr -1 A1835 SFR > 100 Mo yr-1 Pcav ~ 1045 erg s-1

Edge & Frayer 02

~1010 - 1011Mo of gas

• Fuel directly linked to cooling hot halo (not mergers)• X-ray cooling rate near star formation regions match SFR

McN+ 06 Rafferty+08, Cavagnolo+08, Kirkpatrick + 08

A1664 X-ray Hα Lyα

A1835 X-rayR Lyα

cavity

ALMA data will arrive shortly!

star formation cooling time threshold: tcool ~ 500 Myr

blu

e5 x 108 yr

Cool gas & Star formation linked to cooling instabilities in X-ray atmospheres

blue

red

X-ray cooling time

Rafferty + 08

threshold

Cavagnolo + 08 Ha thresholdVoit + 09

Classical cooling flow problem essentially solved: observed SFR ≈ classical cooling rate – heating rate

Upshot of all this:

Rafferty +06, O’Dea +08Best + 06

Gas fueling star formation linked to hot atmospheresthrough cooling time – entropy star formation threshold

Rafferty +08 Cavagnolo +08

Radio-mechanical AGN feedback loopFor reviews McNamara & Nulsen 07 ARAA, 12, NJP

Same process maintains red & dead ellipticals (Bower +06, Croton 06)

Hot Outflows on Cluster Scales

Newer stuff…

Led by Clif Kirkpatrick

MS0735 Cool, metal-enriched outflow

500 ks Chandra imageVLA, HST

McN+09, 12RFe~300 kpc

Pjet~ 3x1046 erg s-1

Fe outflow

Ejet ~ 1062 erg

X-ray metal map

gas hereused to be there

200 kpc

Powerful thrust:

Lifted/displaced mass ~ 1011 M ~1000 Myr-1

See also Simionescu + 08, Kirkpatrick 09,11

metals made hereend up out here

Z=0.3Z

Z~Z

R≈120 kpc

Hydra A Cool, Metal Enriched Outflow

Iron enriched outflow

Kirkpatrick + 09

AGN outflows disperse cool gas & metals into the ICM

Kirkpatrick + 09Gitti + 11

See also Simionescu + 08, O’Sullivan + 11, Nulsen + 05

cool, multiphase gas

ΔMFe = 2-7 x 107 M ΔMtot>1010M Mout > 100 M yr-1

Iron enrichment radius scales with Jet power: drives hot gas out of galaxy

Orientation of outflow correlates with radio and cavity orientation: jet driven outflows

Hydra A

MS0735

Outflow rates of tens to >100 Myr -1 – star formation quenched by heating and removal of metal-enriched, cooling X-ray gas out of BCG and into ICM

Outflow rates comparable to cooling rates of hot atmospheres

Kirkpatrick +09, 11, 12

300 kpc

100 kpc

Metal enrichment radius

AGN jet power

Radio AGN Heating of Cluster Atmospheres Over Time

Finally…

C.J. Ma

See Ma + 11

Problems:

1. Hot atmospheres are ≈1 keV per particle “hotter” than expected? aka, “preheating” problem Kaiser (1991)

2. Quenching & declining numbers of distant cooling flows (Vikhlinin 07, Samuele + 11)

Reviewed by McNamara & Nulsen 12

shock

6 arcmin

380 kpc

Cluster Scale Atmospheric Heating: Hydra A Cluster z=0.05

Wise + 07Nulsen + 05

320 MHz + 8 GHz

McN + 00

Ejet > 1061 erg AGN outburst: swiss cheese morphology to hot atmosphere

X-ray

cooling region

AGN Heating in Distant Clusters

8 serendipitous & all-sky X-ray surveys: 685 ROSAT clusters

Sample:

Procedure:

Cross Correlate cluster X-ray positions with NRAO VLA Sky Survey radio sources

1043 < Lx < 1046 , 0.1 < z < 0.9

Radio detection threshold > 3 mJy

Correct for background as function of flux

Calculate jet power using cavity power scaling relation at 1.4 GHz

Calculate heating rate per particle

C.J. Ma + 2011, and in prep

Challenge: sample selection, jet power proxy

Scaling between jet cavity (mechanical) power and radio luminosity

1.4 GHz 200-400 MHz

Cavagnolo + 10Birzan + 04,08

Pcav ~ 100 Lrad

Lradio (1040 erg s-1)

P cav (

1042

erg

s-1

)

Z>0.3 MACS Clusters Hlavacek-Larrondo + 11

Saturated scalingwhat happens here?

Ma + in prep

excluding powerful radio sources

including powerful radio sourcessaturated scaling

Constant heating from z=2Evolution of radio LF from z=2

- Heating (jet power) rises slowly with X-ray atmospheric luminosity, and redshift

- Heating per gas particle dominant in low-mass clusters

- Gradual heating over time significan addition to Kaiser’s “preheating” scenario

Consequences: excess entropy in clusters (Voit 05, Kaiser 91) declining numbers of distant cooling flows (Santos 10, Vikhlinin 06, Samuele 11)Caveat: calibration of mechanical heating at high radio power

Radio/Mechanical Heating Rate in clusters from z = 0.2-0.7

“preheating rate”

Ma + in prep

R<250 kpc

Summary• Relatively weak radio AGN can be mechanically powerful

• Powerful enough to suppress cooling hot halos

• Strong evidence for a self-regulating feedback loop

• Star formation, jets linked to central X-ray cooling time

• Suppress star formation, disperse metals throughout LSS

• AGN heating important over nearly half the age of universe

• Low-mass X-ray halos heated efficiently

• Gradual AGN heating significant

See McNamara & Nulsen 12, NJP & arXiv for recap of this talk

Ma + 11

J1221+4918z = 0.7Lx = 1.2x1045 erg s-1

kT = 6.5 keV

Host galaxies cannot be identified using NVSS images

X-ray cavities cannot be identified in short X-ray exposures

NRAO-VLA Sky Survey (NVSS)ROSAT X-ray Imaging

Sample hundreds of Clusters from ROSAT

685 clusters, 8 surveys Lx = 3x1043 – 1046 erg s-1

Radio detection fraction ~ 60%

New Large X-ray - Radio Cluster Survey

“normal” clusters