Jet Interactions with the Hot Atmospheres of Clusters & Galaxies 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

optical, radio, X-ray Perseus MS E ~10 59 erg E ~ 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

Cavity Demographics McNamara & Nulsen 07, ARAA nuclear distance cavity radius crossingsage

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

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 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 = 2800 Lobes only {P cav /L rad } med = 120 t Hubble t radio = E cav /L rad = radio cooling timescale Birzan 07 radio ages t cool,x Cyg A Rafferty 06 Birzan 04 HCG 62

Synchrotron age versus dynamical age Birzan 2007, PhD 1:11:1 t cav > t syn Projection? R 0 ? V 0 ? 9/18

Lobes out of equipartition equipartition pressure balance Birzan 2007, PhD k = 1 Dunn & Fabian 04

Jet Composition jet lobe E = pV... gas pressure De Young 2006 P=nkT Energy density in jet energy density e - gas pressure >> 1 Decollimaton for v j > 0.5c Cold protons, Poynting flux magnetic collimation? (won’t see jet)

X-ray/Radio Constraints on Lobe Content variables: magnetic field, B, ratio of protons to electrons, k X-ray Radio Additional constraints: t syn = t buoy, equipartition B eq (k) pressure balance B p (k) from detectability considerations

Particle & Magnetic Field content: large k see also, Dunn, Fabian, Taylor 2005 Dunn & Fabian 2004 Birzan 2007 Gray: determine B buoy (t syn =t buoy ), solve for k Hatched: equipartition between k & B k >> 1, large spread Equipartition between B, k implies assume pressure balance

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 t cav ? 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 = 9x10 60 erg s -1 t = 140 Myr Radio: Lane et al. 04/Taylor Low Radio Frequency Traces Energy 74 MHz Wise et al. 07

shock 6 arcmin 380 kpc Hydra A Wise et al erg Nulsen et al. 05 t shock = 140 Myr t buoy = 220 Myr t buoy > t shock 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.

shock 6 arcmin 380 kpc Hydra A McNamara 95 McNamara et al. 00 U-band Wise 05