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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
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Papers and Posters 1) Basic model: Li et al. ApJ, 2006 2) Jets in Static Clusters: Nakamura, Li, Li, ApJ, 2006, 2007 3) Comparison w. X-ray Bubbles: Diehl et al. ApJ, 2008 4) Comparison w. Herc A Observ: Nakamura et al. ApJ, 2008 5) Cosmological MHD Jet+Cluster Simulation: Xu et al. ApJL, 2008 6) 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.
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Hydra A (Wise et al.) Jets and Lobes in Galaxy Clusters : Effects of ICM Dynamics ? MS0735.6+7421 (McNamara et al.) ~ 400 kpc ~ 1 Mpc Perseus (Fabian et al.) ~ 250 kpc
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Leahy et al. (1996)
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disk Poloidal flux: ~ 10 4 (10 14 ) 2 ~ 10 32 (G cm 2 ) Toroidal flux: ~ ( t) G cm 2 ) Current: I ~ B R ~ 10 18 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
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Li et al. 2006; Nakamura, Li, Li 2006; 2007
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Li (2008) With Both Magnetic and Kinetic Injections I pol r0r0
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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
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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
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Effects of Flows: Stabilization Run F Run E
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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
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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
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Magnetic/Thermal log 10 (e B /e th ) Magnetic/Kinetic log 10 (e B /e k ) Run F: Jets/Lobes are mostly magnetically dominated
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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.
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Analysis of 64 Bubbles in 32 Clusters See Poster by Diehl (Diehl et al. 2008) magnetic Hydro Adiabatic expansion
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Cosmology Ideal-MHD Code Xu et al. (2008, method paper)
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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 128 3 root grid from z=30, followed with 8 level refinements (~8kpc/h) for magnetic fields. Cosmological AMR+MHD Simulation (see H. Xu’s poster)
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Cluster formation with an AGN feedback (Xu et al. 2008) X-ray Intensity
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Magnetic Energy Evolution
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Lobes are magnetically dominated
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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
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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 = 0.248462 (Mpc) Mvir = 3.04303e+13 (M_solar) Mvir (gas) = 1.51376e+12 (M_solar) Mvir (dm) = 2.89165e+13 (M_solar)
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T=108Myr T=228Myr
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T=348My r T=528Mry
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T=648Myr T=768Myr
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T=1.02Gyr T=1.38Gyr
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T=2.10Gyr T=2.82Gyr
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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
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