Centaurus A: Some. Core Physics. Geoff Bicknell 1 Jackie Cooper 1 Cuttis Saxton 1 Ralph Sutherland 1 Stefan Wagner 2

Transcription

1 Movies available at: and Centaurus A: Some Credit: Helmut Steinle Core Physics Geoff Bicknell 1 Jackie Cooper 1 Cuttis Saxton 1 Ralph Sutherland 1 Stefan Wagner 2 1. Research School of Astronomy Astrophysics, ANU 2. Landessternwarte, University of Heidelberg

2 This talk Transition to turbulence TeV emission Jet-cloud interactions in core 2

3 Transition to turbulence Transonic flow Flaring region: supersonic -> transonic transition Relativistic supersonic jet Credit: Hardcastle et al

4 Decelerating relativistic jets (GB ApJ `95) R = ρc2 4p Perturbation V Critical Mach Number M c = 1 + sec 2 θ γ 2 4

5 Expect transition to turbulent flow around ~ Laing and colleagues: Analysis of brightness asymmetries of 8 FR1 jets Transition occurs around 0.8 c 5

6 From GB, ApJ, 1984 Transition to fully turbulent flow involves immersed shocks Symmetric shocks perturbed by m=1 KH instability 6

7 TeV emission: Example PKS Credits: Piner, Plant & Edwards Credits: HESS consortium 7

8 Example of fitting spectrum ATOM RXTE Swift HESS 8

9 Example of fitting spectrum ɛ 1 = 2.0 ev ɛ b = ev ɛ 2 = ATOM RXTE Swift HESS 8

10 Example of fitting spectrum ɛ 1 = 2.0 ev ɛ b = ev ɛ 2 = γ 1 = γ b = γ 2 = ATOM RXTE Swift HESS 8

11 Example of fitting spectrum ɛ 1 = 2.0 ev ɛ b = ev ɛ 2 = ɛ = 3 2 e m e c B γ2 γ 1 = γ b = γ 2 = ATOM RXTE Swift HESS 8

12 Example of fitting spectrum ɛ 1 = 2.0 ev ɛ b = ev ɛ 2 = ɛ = 3 2 e m e c B γ2 γ 1 = γ b = γ 2 = ATOM B = G R = cm K = cm 3 RXTE Swift δ = 40 HESS 8

13 Shock spectrum If electrons accelerated at shock and cool in constant magnetic field in a region of size L then volume averaged shock spectrum given by: N(γ) = Kγ b a 1 γ (a+1) where γ b = v sh = Kγ b a 1 γ (a+1) AL [1 (1 γγb ) a 1 ] γ > γ b γ < γ b 9

14 Soft photon spectrum Klein-Nishina effects limit soft photons to low energy and scattering electrons to high energy ɛ 0 < δ 2 (m ec 2 ) 2 ɛ ) 1 ( 0.26 δ 2 ɛ TeV ɛ ( γ > δm e c δ 1 ɛ TeV ) Soft photon input: 0.1 x Blackbody with mean temperature ~ 200 K 10

15 AX1C possible site of TeV emission Hard X-ray synchrotron spectrum indicates reasonable population of high energy electrons 11

16 Centaurus A Unusual spectrum extending from peak at ~ 100 kev to beyond a TEV External Inverse Compton fit 12

17 Parameters a = 2 β = 0.8 θ = 60 δ =1.44 ɛ b = 0.2 ev γ 1 = 22 γ b = γ 2 = B = =2 Equipartition Energy density = ergs cm 3 T dust = 200 K τ dust =

18 PPMLR simulation code 14 13

19 PPMLR simulation code Based upon Godunov method of numerical hydrodynamics 14 13

20 PPMLR simulation code Based upon Godunov method of numerical hydrodynamics Piecewise Parabolic Method with Lagrangian remap (PPMLR) and Riemann solver 14 13

21 PPMLR simulation code Based upon Godunov method of numerical hydrodynamics Piecewise Parabolic Method with Lagrangian remap (PPMLR) and Riemann solver Originated from VH1 code (University of Virginia and University of Nth Carolina) 14 13

22 PPMLR simulation code Based upon Godunov method of numerical hydrodynamics Piecewise Parabolic Method with Lagrangian remap (PPMLR) and Riemann solver Originated from VH1 code (University of Virginia and University of Nth Carolina) Added cooling of thermal gas 14 13

23 PPMLR simulation code Based upon Godunov method of numerical hydrodynamics Piecewise Parabolic Method with Lagrangian remap (PPMLR) and Riemann solver Originated from VH1 code (University of Virginia and University of Nth Carolina) Added cooling of thermal gas Code for correcting numerical shock instabilities 14 13

24 Jet + Disk simulations (Sutherland & GB 2007, ApJS, 173) Description of the ambient cloudy medium Log-normal density distribution affects the porosity of the medium Kolmogorov power-law of density in Fourier space Both arise naturally in a turbulent medium Mean density that of an almost Keplerian disk supported vertically by thermal and supersonic turbulent pressure

25 Initial mean density 16 15

26 Initial mean density 16 15

27 Initial mean density 2-component dark + luminous matter potential 16 15

28 Initial mean density 2-component dark + luminous matter potential 16 15

29 Initial mean density 2-component dark + luminous matter potential 16 15

30 Parameters of jet and ISM Scale = 1 kpc M = 26 η = L K = ergs s 1 n hot = cm 2 T hot = K n cl = 10 cm 3 T cl = 10 4 K Relativistic equivalent Γ = 5 χ = ρc2 4p =

31 Jet and large scale disk log (density) Resolution =

32 Jet and large scale disk log (density) Resolution =

33 Jet and large scale disk log (density) Evolutionary phases: Resolution =

34 Jet and large scale disk log (density) Evolutionary phases: Flood and channel Resolution =

35 Jet and large scale disk log (density) Evolutionary phases: Flood and channel Pseudo-spherical energydriven bubble Resolution =

36 Jet and large scale disk log (density) Evolutionary phases: Flood and channel Pseudo-spherical energydriven bubble Rapid jet breakout Resolution =

37 Jet and large scale disk log (density) Evolutionary phases: Flood and channel Pseudo-spherical energydriven bubble Rapid jet breakout phase Classical radio galaxy Resolution =

38 Pole-on view Looking into the eye of the Vulcano 19 18

39 Pole-on view Looking into the eye of the Vulcano 19 18

40 Radio morphology and dynamics Synchrotron emissivity: 20 19

41 Radio morphology and dynamics Synchrotron emissivity: 20 19

42 Comparison of adiabatic and radiative clouds - Jackie Cooper PhD thesis Adiabatic Radiative 21 32

43 Comparison of adiabatic and radiative clouds - Jackie Cooper PhD thesis Adiabatic Radiative 21 32

44 Comparison of adiabatic and radiative clouds - Jackie Cooper PhD thesis Adiabatic Radiative 21 32

45 Hierarchy of scales (Saxton et al. 2005) 22

46 That s it! 23