Feedback Driven by Radio Sources Brian McNamara University of Waterloo Baltimore, STScI May, 9 2012 Perimeter Institute for Theoretical Physics Harvard-Smithsonian Center for Astrophysics llaborators: P. Nulsen (CfA), H. Russell, CJ Ma, C. Kirkpatrick (Waterloo) M. Wise (Astron), K. Cavagnolo (Waterloo), A. Vikhlinin
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 Presentation
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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
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