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

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Presentation on theme: "Spectral modeling of cosmic atomic plasmas Jelle S. Kaastra SRON."— Presentation transcript:

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 2

3 Fe XVII The importance of accurate atomic data 3

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! 4

5 Resonance scattering & turbulence 5

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

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

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

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

10 3C/3D lines (Bernitt et al. 2012) 3C: 2p 6 1 S 0 – 2p 5 3d 1 P 1 (resonane) 3D: 2p 6 1 S 0 – 2p 5 3d 3 D 1 (forbidden) Forbidden line occurs due to mixing Excite Fe XVII using laser Allows to measure individual oscillator strengths 10

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! 11

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? 12

13 Ionisation & recombination 13

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

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

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

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

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

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 19

20 Different versions of Cloudy the 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 20

21 Differences photo-ionisation models 21

22 Inner-shell transitions 22

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

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) 24

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

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

27 X-ray absorption Nasty correction factors are interesting! 27

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 28

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

30 Oxygen complexity 30

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

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? 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 Mg silicate Metallic iron FeS Crystal olivine, pyroxene With Mg Glassy structure + FeS Cosmic rays+radiation Sulfur evaporation GEMS

34 Final remarks We showed examples of different & challenging astrophysical modeling All depend on availability reliable atomic data The SPEX code (www.sron.nl/spex) allows to do this spectral modeling & fitting Code & its applications continuing development (since start 1972 by Mewe) 34


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