Toward models of light relativistic jets interacting with an inhomogeneous ISM

Transcription

1 Toward models of light relativistic jets interacting with an inhomogeneous ISM Alexander Wagner Geoffrey Bicknell Ralph Sutherland (Research School of Astronomy and Astrophysics) 1

2 Outline Introduction Motivation Model ingredients FLASH 3 Computing facilities Jet parameters ISM structure 2D test simulations (slab jet) with CenA parameters Near future work 2

3 Introduction Motivation Galactic feedback Magorrian relation (From Häring & Rix 2004) M-σ relation (Tremaine et al 2002) Downsizing Star formation Cooling flow Is the Silk & Rees (1998) picture applicable to AGN jets? Can jet momentum be isotropically distributed? Jet-ISM interactions are probably most important in early phases of a radio galaxy (CSS, GPS) What is the relevance of clouds in jet-ism interactions? 3

4 Introduction Motivation Observational evidence for jet-ism interactions Fast neutral gas outflows in many radio galaxies (Morganti et al 2005) High velocity outflows of optical emission line gas (Nesvadba 2006,7,8) MRC (z = 2.42) [OIII] velocity map [OIII] FWHM Warm line emitting gas is co-spatial with radio lobes (Young et al. 2005) ( alignment effect ) Chandra studies of 3C (Tadhunter et al. 2000), 3C 265 (Solorzano-Inarrea & Tadhunter 2003), PKS (Young et al. 2005) 4

5 Introduction Motivation Evidence for Jet-ISM interactions in Cen A Optical filaments Thermal X-ray knots in NML shocked clouds? Surrounding HI clouds (Schiminovich et al 1994) (Kraft et al 2009) Non-thermal X-ray knots in kpc scale jet efficient particle acceleration in standing shocks (Hardcastle et al 2003, 2007) Back-flow of jet-ionised material? (Neumayer et al 2007) 5

6 Introduction Motivation 3 phase mixing Radio jet hot homogeneous ISM cold inhomogeneous ISM HD Simulations Krause & Alexander (2007) Krause (2008) kpc jet Jet deceleration, mass entrainment, transition to turbulence, & flaring Bicknell (1995), Laing et al. (2008; 3C31) Halo affecting jet? Jet affecting halo? (Kraft et al. 2008) 6

7 Introduction Motivation Global morphology Aims 3C 296 To construct global hydrodynamic models of radio galaxies, in particular CenA, that describe observations over a broad dynamic range. 3C 31 Credit: NRAO/AUI CenA Credit: Alan Bridle, NRAO/AUI Optical: Martel et al 1999 X-ray: NASA/CXC/CfA/ R.Kraft et al; Explore coupling Radio: NSF/VLA/ Univ.Hertfordshire/M.Hardcastle; Optical: ESO/WFI/M.Rejkuba et al.) between jet and the inhomogeneous ISM in view of advancing theories of AGN feedback. 7

8 Model Ingredients FLASH 3 Open source, broad user-base Fortran 90, very modular Relativistic Hydrodynamics Piecewise linear/parabolic interpolation Adaptive mesh: Paramesh 4 Radiative cooling function from MAPPINGSIII code Many other capabilities (MHD, Particles, Poisson solver, cosmology, nuclear reactions) ASC / Alliance Center for Astrophysical Thermonuclear Flashes ( 8

9 Model Ingredients National Computational Infrastructure (hosted at ANU) SGI Altix 3700: 1928 cpu, 1.6 GHz, 3.2 TB memory 3.2 Tflops (peak) SGI Altix Xe: 156 node, 2 quad core 3GHz cpu/node 2 TB memory, 15 Tflops (peak) New Sun cluster now being installed Co(mputational) A(strophysics) La(boratory) at RSAA (PI: Chiaki Kobayashi, PM: Kim Sebo) 128 cpu, 6-9GB/cpu cluster, Infiniband overhead > 100 TB disk storage Up and running by end of this year 9

10 Model Ingredients Relativistic Jet Lorentz factor Γ (speed β) Ratio of proper rest energy density to pressure Jet kinetic luminosity Halo profile (Isothermal self-gravitating halo; self-similar collapse (Shu 1977); cosmological simulations) 10

11 Model Ingredients Inhomogeneous (clumpy) fractal ISM Code written by Ralph Sutherland to generate fractal cube based on algorithm by Lewis & Austin (2002) Fractal two-point statistics. Power-law (with, e.g., Kolmogorov index) in Fourier space. Porosity of ISM Log-normal density distribution with lower density cutoff These statistics arise naturally in turbulent medium 11

12 Model Ingredients Small example (128 cell cube, kmin=2) 3D density scatter 2D slice 12

13 Model Ingredients Previous work that included an inhomogeneous fractal ISM Cooper et al. (2008) Sutherland & Bicknell (2007) 13

14 2D test simulations ( slab jet) Relativistic Jet parameters Lkin=1043 erg s-1 β = 0.8 χ = ρc2/4pjet = 1, 10, 100 Djet base = 30 pc Homogeneous ambient medium parameters Tambient = 0.68 kev ρambient = mp cm-3 (Kraft et al 2008) pjet/pambient = 2600, 730, 89 ρjet/ρambient = 0.012, 0.034,

15 2D test simulations ( slab jet) 15

16 2D test simulations ( slab jet) 370 ky 16

17 2D test simulations ( slab jet) χ = 10 χ = 100 χ=1 Relativistic hydro Piecewise parabolic interpolation χ=1 Non-relativistic hydro with equivalent Fkin=1043 erg cm-3, pjet, jet velocity 17

18 2D test simulations ( slab jet) χ=10 RHD χ=100 RHD χ=1 RHD χ=1 HD 18

19 2D test simulations ( slab jet) χ=10 RHD 340 ky 180 ky χ=100 RHD χ=1 RHD 516 ky 213 ky χ=1 HD 19

20 2D test simulations ( slab jet) Relativisitic HD, χ = 1 Piecewise linear interpolation Piecewise parabolic interpolation 370 ky 370 ky 20

21 Relativisitic HD, χ = 1 Piecewise linear interpolation Piecewise parabolic interpolation 370 ky 370 ky 21

22 2D test simulations ( slab jet) Non-relativistic HD (PPM) 200 ky Relativisitc (PLM) χ=1 200 ky 200 ky Relativistic HD (PLM) χ=100 22

23 Near future work Completion of model Incorporate fractal inhomogeneous ISM Improve equation of state Run full 3D simulations Resolution tests Synthetic radio, X-ray (Thermal, Inverse Compton), and Hα images Study Ω = 2π energy and momentum transport Study onset of turbulence, entrainment rates & knot formation Input & ideas from the observational community are very welcome. 23

24 Appendix Self-similar collapse of Isothermal cloud (Shu 1987) 24

25 Appendix Self-similar collapse of Isothermal cloud (Shu 1987) 25