1. Ralf Siebenmorgen Toulouse June’10  Dust model of the ISM  PAH bands in starburst nuclei  Monte Carlo radiative transfer  PAH destruction in T Tauri disks Frank Heymann (PhD) Endrik Krűgel

2. Ralf Siebenmorgen Toulouse June’10 dust’1990

3. Ralf Siebenmorgen Toulouse June’10 spheroids 1: polarisation Voshchinnikov (2004)

4. Ralf Siebenmorgen Toulouse June’10 2: ‘’2200” bump + 3: PAH absorption Vertraete et al. 1992 Malloci et al. 2007 Schutte et al. 1993 PAH gr

5. Ralf Siebenmorgen Toulouse June’10 Si + aC : 60Å < a < 0.2-0.3µm, ~a -3.5 Graphite: 5Å < a < 80 Å, ~a -3.5 PAH : 30, 200 C ISM [g]: 0.66Si + 0.22aC + 0.07gr + 0.05 PAH [g] extinction’2010

6. Ralf Siebenmorgen Toulouse June’10 mean I S R F

7. Ralf Siebenmorgen Toulouse June’10 “Carbon crisis” abundances [ppm]: 31Si + 150aC + 50gr + 30PAH 4: abundance + 5: PAH bands

8. Ralf Siebenmorgen Toulouse June’10 dust’2010

9. Ralf Siebenmorgen Toulouse June’10 ISO Boulanger et al. (1998) Siebenmorgen et al. (1998) HD97300

10. Ralf Siebenmorgen Toulouse June’10 Siebenmorgen et al. (2001) NGC1808 Radiative transfer in SB

11. Ralf Siebenmorgen Toulouse June’10 post ISO 17 features

12. Ralf Siebenmorgen Toulouse June’10 Siebenmorgen et al. (2001) post ISO

13. Ralf Siebenmorgen Toulouse June’10 Siebenmorgen et al. (2007) post Spitzer SED model grid: luminosity size mass

14. Ralf Siebenmorgen Toulouse June’10 high z Efstathiou & Siebenmorgen (2009)

15. Ralf Siebenmorgen Toulouse June’10 Original code by Krűgel (2006) Arbitrary dust distribution Pseudo adaptive mesh 1. geometry Monte Carlo

16. Ralf Siebenmorgen Toulouse June’10 1. geometry 2. source Source emits “photon packages” of equal energy Monte Carlo

17. Ralf Siebenmorgen Toulouse June’10 1. geometry 2. source 3. inter-action 4. dust temperature absorption / scattering / no interaction Monte Carlo = - ln( ζ)

18. Ralf Siebenmorgen Toulouse June’10 Photons escape model cloud Monte Carlo 1. geometry 2. source 3. inter-action 4. temperature 5. detection

19. Ralf Siebenmorgen Toulouse June’10  store PAH absorption events of each cell  compute PAH emission  neglect PAH self absorption Monte Carlo + PAH

20. Ralf Siebenmorgen Toulouse June’10 Multiple photons at a time: MC parallelization 1.Cell locked when hit by photon 2.Parallel random number generator (Mersene Twister) 3.Computer games Graphical Processing Units (CUDA)

21. Ralf Siebenmorgen Toulouse June’10 1D benchmark sphere Iveciz (99)

22. Ralf Siebenmorgen Toulouse June’10 1D benchmark sphere T * = 2500K ρ (r) = const. A V =10 1 1001000 mag ~5% for 0

23. Ralf Siebenmorgen Toulouse June’10 Method ParallelizationAdvantage Time Benchmark sphere τ~1000) Lucy YES (but floating) Optical thin>1h Bjorkman & Wood Partly (not independent) No iteration5min ourYESGPU<1min MC methods

24. Ralf Siebenmorgen Toulouse June’10 Monte Carlo + PAH

25. Ralf Siebenmorgen Toulouse June’10 Disk: T * = 5800K L * = L sun ρ (r) : hydro static equilibrium (Chiang & Goldreich 1997) Pascucci et al (2004) 2D benchmark

26. Ralf Siebenmorgen Toulouse June’10 2D benchmark disk 0 ~10% for face-on edge-on 1 = 10 100

27. Ralf Siebenmorgen Toulouse June’10 3D proto-planetary disk + spiral MHD (Fargo) density T * = 5800K L * = L sun A v =10mag 8au 3au

28. Ralf Siebenmorgen Toulouse June’10 3D proto-planetary disk + spiral

29. Ralf Siebenmorgen Toulouse June’10 ELT 42m PAH imaging

30. Ralf Siebenmorgen Toulouse June’10 D = 50pc 50mas at 11.3μm PSF dual band + coronograph ELT 42m PAH imaging

31. Ralf Siebenmorgen Toulouse June’10 D = 50pc 50mas at 11.3μm PAH imaging gap /px (μJy /px)

32. Ralf Siebenmorgen Toulouse June’10 PAH detection rate: Herbig AeBe 60% TTS 10% T Tauri stars

33. Ralf Siebenmorgen Toulouse June’10 T Tauri stars

34. Ralf Siebenmorgen Toulouse June’10

35. PAH in a mono-energetic heating bath if | U f – U i – hν | < ½ ΔU f : A fi = K ν F ν / hν Siebenmorgen & Krűgel (2010)

36. Ralf Siebenmorgen Toulouse June’10 Arrhenius form: t dis ~ exp(E o /kT) / ν 0 « t cool /f ~ 1s T min = E o /k ln(ν 0 ) ~2000K; E b ~ 5eV; ν 0 = 10 13 Hz ΔE = 3N c kT min ~ 0.1 N c. E o => N c < 2 ΔE /[eV] (PAH unstable) EoEo T [K] time t cool t abs ~ 1h Omont (1986); Micedlotta et al. (2010); Tielens (2005) Unimolecular dissociation: PAH destruction

37. Ralf Siebenmorgen Toulouse June’10 Unimolecular dissociation: t dis ~ exp(E o /kT) / ν 0 « t cool /f ~ 1s T min = E o /k ln(ν 0 ) ~2000K; E o ~ 5eV ΔE = 3N c kT min ~ 0.1 N c. E o => N c < 2 ΔE /[eV] (PAH unstable) EoEo PAH destruction 1) single hard photon : independent of distance 2) many soft photons : ~ 1AU

38. Ralf Siebenmorgen Toulouse June’10 Stationary disk Sufficient X-ray photons? α ℓ τ = 1 z I } # C in PAH # hard γ absorption/sec << TT phase ‘PAH removal time’ top surface layer Σ ℓ = α/κ = h ν ∙ 4 π r 2 /Lκ

39. Ralf Siebenmorgen Toulouse June’10 Vertical mixing in disk? ℓ /v ┴ = t exp > N C t abs PAH replenishment Siebenmorgen & Krűgel (2010)

40. Ralf Siebenmorgen Toulouse June’10 Future  Heating: photosph.+FEUV + X-rays  Dust + Gas  Density structure  PAH emission + destruction MC model of T Tauri disks

41. Ralf Siebenmorgen Toulouse June’10 Conclusion ?