Jet Interactions with the Hot Atmospheres of Clusters & Galaxies

1. 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

2. E ~ 1062 erg E ~1059 erg MS0735.6+7421 Perseus ghostcavity 1’= 20 kpc 1’ = 200 kpc weak shock M=1.3 shock McNamara et al. 05 Fabian et al. 05 optical, radio, X-ray

3. Cavity Energetics & Kinematics r

4. Cavity Demographics cavity radius nucleardistance crossings age McNamara & Nulsen 07, ARAA

5. 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

6. Can we use X-ray cavities to understand radio sources? Hmm…Kerosene. Must be a heavy jet.

7. Using X-ray Halos as Jet Calorimeters Energy = magnetic fields + particles X-ray Radio • Laura Birzan’s thesis: 24 systems, VLA data at 0.327, 1.4, 4.5, 8.5 GHz, Chandra imaging • Largely clusters & groups • low specific accretion rates << Eddington (Rafferty 06) Constrain: ages/dynamics, magnetic field & particle content, equipartition

8. Enormous range in radiative efficiency Birzan 07 Rafferty 06 Birzan 04 Lobes only tHubble Cyg A HCG 62 tcool,x radio ages <Pcav/Lrad> = 2800 tradio = Ecav/Lrad = radio cooling timescale {Pcav/Lrad}med = 120

9. Synchrotron age versus dynamical age tcav > tsyn Projection? R0 ? V0 ? 1:1 Birzan 2007, PhD 9/18

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

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

12. X-ray/Radio Constraints on Lobe Content X-ray Radio from detectability considerations variables:magnetic field,B, ratio of protons to electrons, k Additional constraints:tsyn = tbuoy, equipartition Beq (k) pressure balanceBp (k)

13. Particle & Magnetic Field content: large k Birzan 2007 Gray: determine Bbuoy(tsyn=tbuoy), solve for k Hatched: equipartitionbetween k & B assume pressure balance see also, Dunn, Fabian, Taylor 2005 Dunn & Fabian 2004 k >> 1, large spread Equipartition between B, k implies

14. Additional Issues Thermal pressure support for cavities? Tgas > 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…

15. Z=0.053 Hydra A: Complex Dynamics Wise et al. 07

16. Low Radio Frequency Traces Energy Shock M = 1.34 E = 9x1060 erg s-1 t = 140 Myr Radio: Lane et al. 04/Taylor Wise et al. 07 74 MHz

17. Hydra A shock 6 arcmin 1061 erg Nulsen et al. 05 380 kpc Wise et al. 07 tshock= 140 Myr tbuoy= 220 Myr tbuoy > tshock MHD jets?

18. 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.

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