Magnetic Jets and Lobes in Cosmological MHD Hui Li Los Alamos National Laboratory NSF/DOE Center for Magnetic Self-Organization (CMSO) Collaborators: H. Xu, D. Collins, S. Li, M. Morman  Overview of Observations and Magnetic Jet Model  Results on 3D MHD Jet/Cluster Simulations  Results on Cosmological MHD Jet/Cluster Simulations

Papers and Posters 1) Basic model: Li et al. ApJ, ) Jets in Static Clusters: Nakamura, Li, Li, ApJ, 2006, ) Comparison w. X-ray Bubbles: Diehl et al. ApJ, ) Comparison w. Herc A Observ: Nakamura et al. ApJ, ) Cosmological MHD Jet+Cluster Simulation: Xu et al. ApJL, ) Long-time evolution of magnetic bubble: Liu et al. ApJL, submitted Both Steven Diehl and Hao Xu have posters at this meeting. We are also looking for a postdoc in this area.

Hydra A (Wise et al.) Jets and Lobes in Galaxy Clusters : Effects of ICM Dynamics ? MS (McNamara et al.) ~ 400 kpc ~ 1 Mpc Perseus (Fabian et al.) ~ 250 kpc

Leahy et al. (1996)

disk   Poloidal flux:  ~ 10 4 (10 14 ) 2 ~ (G cm 2 )  Toroidal flux:  ~ (  t)        G cm 2 )  Current: I ~ B R ~ A  Mag. energy injection rate: dE mag /dt = I z V - P loss  Expansion: I z (r,t),  (r,t), and P loss (r,t). BH Li et al. (2006) Astrophysical Jets: Engine and Injection I pol r0r0

Li et al. 2006; Nakamura, Li, Li 2006; 2007

Li (2008) With Both Magnetic and Kinetic Injections I pol r0r0

3D MHD Simulations Cluster: isothermal, hydrostatic (initially) T = 4 keV, n c = 0.01 (1/cm 3 ), R c = 40 kpc;  = 0.5 Jets in Static Clusters: injection time: 40 Myr injection magnetic energy: ~ 3x10 60 ergs (~2.5x10 45 ergs/s) mass injection rate: < M sun / yr

Magnetic field and current distribution (as kinetic energy injection increases…) E B = 2.6x10 60 ergs E k < 2.6x10 56 ergs E B = 1.8x10 60 ergs E k = 0.7x10 60 ergs E B = 1.6x10 60 ergs E k = 2.3x10 61 ergs Run A Run BRun C

Effects of Flows: Stabilization Run F Run E

Alfven Speed (run F) Alfven speed (run E) Flow Speed (run F) Flow Speed (run E) Radius Velocity  Sub-Alfvenic  with shear  Supersonic Azimuthally averaged velocity profile at z=3

Run E: without E k injectionRun F: with E k injection Comparison of Energy Evolution E inj = E Binj E inj =E Binj +E Kinj EBEB EBEB E th EKEK EKEK EgEg EgEg

Magnetic/Thermal log 10 (e B /e th ) Magnetic/Kinetic log 10 (e B /e k ) Run F: Jets/Lobes are mostly magnetically dominated

Estimating Magnetic Fields and Energy Density R lobe Measuring B: could be small in the main volume. But magnetic energy contained in the central region is a sizable fraction of the total lobe.

Analysis of 64 Bubbles in 32 Clusters See Poster by Diehl (Diehl et al. 2008) magnetic Hydro Adiabatic expansion

Cosmology Ideal-MHD Code Xu et al. (2008, method paper)

Developed AMR+MHD and implemented in ENZO code. ENZO AMR+Hydro simulation: h=0.7,  m =0.3,  b =0.026,  =0.7,  8 =0.928 Volume: 256 Mpc/h Initial root grid from z=30, followed with 8 level refinements (~8kpc/h) for magnetic fields. Cosmological AMR+MHD Simulation (see H. Xu’s poster)

Cluster formation with an AGN feedback (Xu et al. 2008) X-ray Intensity

Magnetic Energy Evolution

Lobes are magnetically dominated

Heating the Cluster Core Region (see Hao Xu’s poster) Change of inflow mass of clusters with and without AGN injection T=36 Myr T=156 Myr T=336 Myr T=670 Myr

Magnetic jet input at high redshift Magnetically dominated jet input at a halo at z=3 size: 80 Mpc comoving Injection B fields strength: 40 microgauss Halo properties: Rvir = (Mpc)‏ Mvir = e+13 (M_solar)‏ Mvir (gas) = e+12 (M_solar)‏ Mvir (dm) = e+13 (M_solar)‏

T=108Myr T=228Myr

T=348My r T=528Mry

T=648Myr T=768Myr

T=1.02Gyr T=1.38Gyr

T=2.10Gyr T=2.82Gyr

Summary  Jets/lobes as magnetically dominated system with large current  “Flaring”/Lobe formation related to background ICM pressure profile (coupled with 3D MHD instability)  Lobe size determined by balance between external pressure and total current  Magnetic energy is gradually converted to thermal and kinetic energies of the jet/lobes  Morphology of jet/lobe is heavily influenced by background ICM dynamics, though magnetic fields crucial in maintaining the integrity of jets/lobes  Relic evolution, leading to magnetization of ICM/IGM