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Spectral modeling of cosmic atomic plasmas

Spectral modeling of cosmic atomic plasmas. Jelle S. Kaastra SRON. Topics covered in this talk. Fe XVII Collisional onisation & recombination rates Inner shell transitions Interstellar absorption. Fe XVII. The importance of accurate atomic data. The importance of Fe XVII.

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Spectral modeling of cosmic atomic plasmas

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  1. Spectral modeling of cosmic atomic plasmas Jelle S. Kaastra SRON

  2. Topics covered in this talk • Fe XVII • Collisional onisation & recombination rates • Inner shell transitions • Interstellar absorption

  3. Fe XVII The importance of accurate atomic data

  4. The importance of Fe XVII • Stable ion (Ne-like) • Coldest Fe ion emitting in Fe-L band (cool core clusters) • Has handful of strong lines  consistency checks • Strongest resonance line has large f resonance scattering effects useful diagnostic!

  5. Resonance scattering & turbulence

  6. Resonance scattering(NGC 5813, de Plaa et al. 2012)

  7. Measured and predicted line ratios(de Plaa et al. 2012)

  8. Results • NGC 5813: vturb = 140-540 km/s (15-45% of pressure) • NGC 5044: vturb >320 km/s (> 40% turbulence)

  9. Fe XVII spectrum Capella(Bernitt et al. 2012) 15.01 Å 16.78, 17.06, 17.10 Å 15.27 Å

  10. 3C/3D lines(Bernitt et al. 2012) • 3C: 2p61S0 – 2p53d 1P1 (resonane) • 3D: 2p61S0 – 2p53d 3D1 (forbidden) • Forbidden line occurs due to mixing • Excite Fe XVII using laser • Allows to measure individual oscillator strengths

  11. Resulting oscillator strength • Observed ratio of oscillator strengths 71% smaller than e.g. NIST value and others • If due to 3C line, than also in emission lower fluxes!

  12. Groups revisited • Implications Bernitt et al.: model X/3C 40% higher • Resonance scattering makes observed X/3C higher • Source like NGC 5044 would fall below line! • Should full effect be attributed to 3C alone? Or also to 3D?

  13. Ionisation & recombination

  14. Ionisation balance Bryans et al. 2009 example: Fe @ 1 keV

  15. Bryans et al. in NEIwork done with Makoto Sawada(T= 2 keV, compared to AR92)

  16. Larger differences for Ni(T = 2 keV)

  17. Recombining plasma(Fe; T=2 keV T = 0.6 keV)

  18. Non-thermal electrons(2 keV + 10% 20 keV)

  19. Effects of DR on photoionised plasmas • Kraemer et al. (2004): calculations for Fe with & without low-T DR • Compare to O ions: • Differences up to factor 2 • May explain “mismatch” in Seyfert galaxy fits

  20. Different versions of Cloudythe effects of dielectronic recombination updates • Chakravorty et al. 2008: • Same ionising continuum (Γ=1.8) • Differences in number & location stable branches • Due to updated DR rates

  21. Differences photo-ionisation models

  22. Inner-shell transitions

  23. The Fe UTA • UTA = UnresolvedTransition Array, blend of narrow features • Due to inner-shell transitions • Almost no accurate atomic data available before Sako et al. (2001)

  24. Calculations & Lab measurements of inner-shell transitions • Example: oxygen K-shell transitions (Gu et al. 2005) • Lab measurements: EBIT • Calculations: FAC •  accurate λ for O V 1s-2p main line: uncertainty only 3 mÅ (50 km/s)

  25. Sample spectraRGS 600 ks, Detmers et al. 2011 (paper III)

  26. Example: AGN outflow Mrk 509 (Detmers et al. 2011)

  27. X-rayabsorption Nasty correction factors are interesting!

  28. Interstellar X-ray absorption • High-quality RGS spectrum X-ray binary GS1826-238 (Pinto et al. 2010) • ISM modeled here with pure cold gas • Poor fit

  29. Adding warm+hot gas, dust Adding warm & hot gas Adding dust

  30. Oxygen complexity

  31. Interstellar dust • SPEX (www.sron.nl/spex) currently has 51 molecules with fine structure near K- & L-edges • Database still growing (literature, experiments; Costantini & De Vries) • Example: near O-edge (Costantini et al. 2012) Transmission 23.7 Ang 22 Ang

  32. Absorption edges: more on dust • optimal view O & Fe • Fe 90%, O 20% in dust (Mg-rich silicates rather than Fe-rich: Mg:Fe 2:1 in silicates) • Metallic iron + traces oxydes • Shown: 4U1820-30, (Costantini et al. 2012)

  33. Are we detecting GEMS? FeS GEMS= glass with embedded metal & sulphides (e.g. Bradley et al. 2004) interplanetary origin, but some have ISM origin  invoked as prototype of a classical silicate Crystal olivine, pyroxene With Mg Cosmic rays+radiation Metallic iron Mg silicate Glassy structure + FeS Sulfur evaporation GEMS

  34. Finalremarks • We showedexamplesof different & challengingastrophysicalmodeling • Alldepend on availability reliableatomic data • The SPEX code (www.sron.nl/spex) allowsto do thisspectralmodeling & fitting • Code & itsapplicationscontinuingdevelopment (since start 1972 byMewe)

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