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NGC 1275
Perseus-Pisces Supercluster, 75 Mpc, mass ~8×1015 Msun
Perseus Cluster, 75 Mpc, 500 galaxies, M~2×1015 Msun
NGC 1275
[O II]                                       H I + [N II]                     HI                              [S II]      ...
Strong H2 lines in IR                        H2           H2                        Johnstone et al 2007, MNRAS, 382, 1246
CO lines: Mmolecule ~ 1011 Msun           CO 1-0                          Salome et al 2006, A&A, 454, 4376
Astronomical context Atomic,   molecular  gas ~70 pc wide,  6 kpc long B~100 mG for  magnetic support ~70 km/s turbule...
Spectrum of a non-equilibrium gas Detailed  microphysics Energetic radiation &  particles interact with gas Ejected ele...
Cloudy  Follows  the detailed microphysics, with   minimum compromise  All stages of ionization of the lightest 30   ele...
10                           1  ν fν [erg cm-2 s-1]    0.1                        0.01                        10−3        ...
The big questions  What   powers emission from the filaments?  How   is the strange optical spectrum produced?   – Inver...
Three possible energy sources  Starlight    – Photoionization as in HII regions or planetary      nebulae  Heat   deposi...
And ionization/recombination processes   Starlight     – Valence shell photoionization     – Radiative/dielectronic recom...
 Ionizing particles                     entering …                    Ionized gas                      – Heat           ...
These three processes producevery different ionization ratios
Photons vs particles
Photons vs particlesPhotoionization – RR&DR electron recombination rates ~10-13 cm3 s-1,photoionization cross sections few...
Photons vs particlesIonizing particles – O, N ionization strongly coupled to H by resonantcharge exchange
Thermal vs ionizing particles
Thermal vs ionizing particles   Recombination by      Electron impact   CX, RR, DR            ionization with             ...
The curious ionization ratios   are produced by ionizingparticles entering molecular gas
Observed / predicted spectrum                              10                                     H I, [N I],       predic...
Predicted spectrum
Optical/UV spectrum
Radio
X-ray
Conclusions Filaments  powered by penetration of surrounding  hot gas (Fabian+ 2011) Suprathermal ionization followed by...
Powering the intra-cluster filaments in cool-core clusters of galaxies
Powering the intra-cluster filaments in cool-core clusters of galaxies
Powering the intra-cluster filaments in cool-core clusters of galaxies
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Powering the intra-cluster filaments in cool-core clusters of galaxies

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Talk presented by Gary Ferland at the 17th International Conference on Atomic Processes in Plasmas, Queen's Univesrity Belfast, 19-22 July 2011.

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Transcript of "Powering the intra-cluster filaments in cool-core clusters of galaxies"

  1. 1. NGC 1275
  2. 2. Perseus-Pisces Supercluster, 75 Mpc, mass ~8×1015 Msun
  3. 3. Perseus Cluster, 75 Mpc, 500 galaxies, M~2×1015 Msun
  4. 4. NGC 1275
  5. 5. [O II] H I + [N II] HI [S II] [O I] HI HI He I [N I] (Å)H I, He I recombination, low ionization lines, [N I] Inverted ionization ratios Unlike any starlight-ionized nebulae Hatch+ in preparation
  6. 6. Strong H2 lines in IR H2 H2 Johnstone et al 2007, MNRAS, 382, 1246
  7. 7. CO lines: Mmolecule ~ 1011 Msun CO 1-0 Salome et al 2006, A&A, 454, 4376
  8. 8. Astronomical context Atomic, molecular gas ~70 pc wide, 6 kpc long B~100 mG for magnetic support ~70 km/s turbulence Surrounded by ~5 keV gas with nT~3×106 cm-3 KFabian+ 2008 Nature
  9. 9. Spectrum of a non-equilibrium gas Detailed microphysics Energetic radiation & particles interact with gas Ejected electrons heats, excite & ionize gas Ionization drives chemistry Full spectrum predicted – Detailed chemistry, grain physics
  10. 10. Cloudy  Follows the detailed microphysics, with minimum compromise  All stages of ionization of the lightest 30 elements, 100+ molecules  2.7 K ≤ T ≤ 1010 K  10-10 ≤ n ≤ 1020 cm-3  Continuously maintained  Fully open source, at www.nublado.org  Ryan Porter, Peter van Hoof, Robin Williams
  11. 11. 10 1 ν fν [erg cm-2 s-1] 0.1 0.01 10−3 100 1000 100 10ν fν [erg cm-2 s-1] 1 0.1 0.01 10−3 10−4 1 10 100 1000 Wavelength (μm)
  12. 12. The big questions  What powers emission from the filaments?  How is the strange optical spectrum produced? – Inverted ionization ratios, strong [N I] emission – Strong molecular emission, including H2, CO, and HCN – Unlike anything seen in H II regions or planetary nebulae  Filaments trace feedback between massive black hole in central galaxy and the intracluster medium. How and why?
  13. 13. Three possible energy sources  Starlight – Photoionization as in HII regions or planetary nebulae  Heat deposition – dissipative MHD waves – shocks  Ionizing particles entering molecular gas – Intracluster medium (5 keV) – radio lobes (MeV) – or produced in situ
  14. 14. And ionization/recombination processes  Starlight – Valence shell photoionization – Radiative/dielectronic recombination  Heat deposition – Collisional ionization – Radiative/dielectronic recombination  Ionizing particles – primary impact ionization – secondary impact ionization, excitation, heating – charge exchange recombination
  15. 15.  Ionizing particles entering …  Ionized gas – Heat  Atomic/molecular gas – Shower of suprathermal electrons – Secondary excitation and ionization – less heating – Rich ion-molecule chemistry  Energetic photons have same effectsAIRES, U Chicago
  16. 16. These three processes producevery different ionization ratios
  17. 17. Photons vs particles
  18. 18. Photons vs particlesPhotoionization – RR&DR electron recombination rates ~10-13 cm3 s-1,photoionization cross sections few megabarns
  19. 19. Photons vs particlesIonizing particles – O, N ionization strongly coupled to H by resonantcharge exchange
  20. 20. Thermal vs ionizing particles
  21. 21. Thermal vs ionizing particles Recombination by Electron impact CX, RR, DR ionization with Boltzmann factors
  22. 22. The curious ionization ratios are produced by ionizingparticles entering molecular gas
  23. 23. Observed / predicted spectrum 10 H I, [N I], predicted / observed He I, [O I], H2 H2, [Ne II] [N II], [S II] 1 0.1 1 10 wavelength (microns)Ferland+ 2009MNRAS.392.1475F
  24. 24. Predicted spectrum
  25. 25. Optical/UV spectrum
  26. 26. Radio
  27. 27. X-ray
  28. 28. Conclusions Filaments powered by penetration of surrounding hot gas (Fabian+ 2011) Suprathermal ionization followed by charge transfer recombination accounts for odd spectrum Grains must be present to sustain the rich chemistry – Galactic origin rather than condensation from hot gas? Composition within factor of two of ISM Large mass deduced from CO confirmed Large reservoirs of undetectable gas likely Ferland et al, 2008MNRAS.386L..72F, 2009MNRAS.392.1475F
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