feedback driven by radio sources
DESCRIPTION
Brian McNamara. Feedback Driven by Radio Sources. University of Waterloo. Perimeter Institute for Theoretical Physics Harvard-Smithsonian Center for Astrophysics. Baltimore, STScI May, 9 2012. Collaborators: P. Nulsen (CfA), H. Russell, CJ Ma , C. Kirkpatrick (Waterloo) - PowerPoint PPT PresentationTRANSCRIPT
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