Jet Interactions with the Hot Atmospheres of Clusters & Galaxies QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture. B.R. McNamara University of Waterloo Girdwood, Alaska May 23, 2007 L. Birzan, P.E.J. Nulsen, D. Rafferty, C. Carilli, M.W. Wise Harvard-Smithsonian Center for Astrophysics QuickTime™ and a TIFF (Uncompressed) de are needed to see th
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Jet Interactions with the Hot Atmospheres of Clusters & Galaxies
Jet Interactions with the Hot Atmospheres of Clusters & Galaxies. B.R. McNamara. University of Waterloo. Harvard-Smithsonian Center for Astrophysics. L. Birzan, P.E.J. Nulsen, D. Rafferty, C. Carilli, M.W. Wise. Girdwood, Alaska May 23, 2007. E ~ 10 62 erg. E ~10 59 erg. - PowerPoint PPT Presentation
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Jet Interactions with the Hot Atmospheres of Clusters & Galaxies
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B.R. McNamara
University of Waterloo
Girdwood, Alaska May 23, 2007
L. Birzan, P.E.J. Nulsen, D. Rafferty, C. Carilli, M.W. Wise
Harvard-Smithsonian Center for Astrophysics
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optical, radio, X-ray
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Perseus MS0735.6+7421
E ~1059 erg E ~ 1062 erg
1’ = 200 kpc
1’= 20 kpc
Fabian et al. 05 McNamara et al. 05
M=1.3 shock
weak shock
ghost cavity
Cavity Energetics & Kinematics
r
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ts = r /cs
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E =γpV
γ −1≈1055 −1062erg
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tbuoy = r /v t ∝ r / 2gV
Cavity Demographics
McNamara & Nulsen 07, ARAA
nuclear distancecavity radius
crossings age
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N ∝ R−1
Broader Consequences
• Jets may quench cooling flows in clusters, groups, galaxies
• Controlled by feedback: cold/Bondi accretion
• Puzzle: how jets heat the gas
• Galaxy and SMBH formation: luminosity function, “cosmic downsizing”
• Cluster “preheating” ~1/4 keV per particle
• Magnetic fields, halos/relics, CR acceleration, etc.
• New theoretical heating & jet models
• Understanding radio jets themselves
McNamara & Nulsen 07, ARAA
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Hmm…Kerosene. Must be a heavy jet.
Can we use X-ray cavities to understand radio sources?
Using X-ray Halos as Jet Calorimeters
Energy = magnetic fields + particles
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X-ray Radio
Constrain: ages/dynamics, magnetic field & particle content, equipartition
• Laura Birzan’s thesis: 24 systems, VLA data at 0.327, 1.4, 4.5, 8.5 GHz, Chandra imaging
• low specific accretion rates << Eddington (Rafferty 06)• Largely clusters & groups
Enormous range in radiative efficiency
<Pcav/Lrad> = 2800
Lobes only
{Pcav/Lrad}med = 120
tHubble
tradio = Ecav/Lrad = radio cooling timescale
Birzan 07
radio ages
tcool,x
Cyg A
Rafferty 06
Birzan 04
HCG 62
Synchrotron age versus dynamical age
Birzan 2007, PhD
1:1
tcav > tsyn
Projection?R0 ?V0 ?
9/18
Lobes out of equipartition
equipartition
pressure balance Birzan 2007, PhD
k = 1
Dunn & Fabian 04
Jet Composition
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E = pV
. . .
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ε j = E v j tπrj2
gas pressure
De Young 2006
P=nkT
Energy density in jet
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v j = 0.1c
rj = 0.1kpc
t = tsyn, tbuoy
energy density e-
gas pressure>> 1Decollimaton
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E.
Lrad<1 for vj > 0.5c
Cold protons, Poynting flux magnetic collimation?
(won’t see jet)
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E = EB + Ep ∝B2
8πΦV + (1+ k)B
−3
2L rad
X-ray/Radio Constraints on Lobe Content
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Φ ≈1
variables: magnetic field, B, ratio of protons to electrons, k
X-ray Radio
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tsyn ∝B1/ 2
B2 + Bm2ν c (1+ z)[ ]
−1/ 2
€
Beq ∝ Lrad2 7V −2 7 (1+ k) /Φ[ ]
2 7
Additional constraints: tsyn = tbuoy,
equipartition Beq (k) pressure balance Bp (k)
from detectability considerations
Particle & Magnetic Field content: large k
see also, Dunn, Fabian, Taylor 2005 Dunn & Fabian 2004
Birzan 2007
Gray: determine Bbuoy(tsyn=tbuoy), solve for k
Hatched: equipartition between k & B
k >> 1, large spread
Equipartition between B, k implies
assume pressure balance
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B ≥ 50μG
Additional Issues
Thermal pressure support for cavities?
T gas > 20 keV
Blanton et al. 02, Nulsen et al. 02, Gitti et al. 07
Jet/lobe dynamics: how reliable is tcav ?
• reasonable agreement with simulations (eg. Jones & De Young 05)
• factors of several errors likely, but not factors of 10, based on shock constraints
consider Hydra A, for example…
Hydra A: Complex Dynamics Z=0.053
Wise et al. 07
Shock
M = 1.34
E = 9x1060 erg s-1
t = 140 Myr
Radio: Lane et al. 04/Taylor
Low Radio Frequency Traces Energy
74 MHzWise et al. 07
shock
6 arcmin
380 kpc
Hydra A
Wise et al. 07
1061 erg
Nulsen et al. 05
tshock= 140 Myr
tbuoy= 220 Myr
tbuoy > tshock
MHD jets?
Summary
• Cluster radio sources radiatively inefficient• No simple relationship between radio power & jet power• Jet power much higher than early estimates• Synchrotron ages decoupled from dynamical ages• Equipartition invalid in lobes• Ratio of heavy particles (protons) to electrons, k >> 1• Evidence for complex lobe/cavity dynamics (eg. Hydra A)• Poynting jets? See poster by Diehl, Li, Rafferty, et al.