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Dust in the Infrared – a prime tool for AGN diagnostics

Dust in the Infrared – a prime tool for AGN diagnostics. Eckhard Sturm. The QUEST Collaboration. 1/35. Infrared dust spectra can help us to understand AGN torus and NLR - physical properties AGN unification AGN host galaxies AGN – Starburst connection AGN evolution. 2/35. Ices.

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Dust in the Infrared – a prime tool for AGN diagnostics

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  1. Dust in the Infrared – a prime tool for AGN diagnostics Eckhard Sturm The QUEST Collaboration 1/35

  2. Infrared dust spectra can help us to understand • AGN torus and NLR - physical properties • AGN unification • AGN host galaxies • AGN – Starburst connection • AGN evolution • ... 2/35

  3. Ices silicate Silicate Pier & Krolik 92 The dust components of mid-infrared galaxy spectra 3/35

  4. I) The continuum 4/35

  5. Weedman et al. 2005 5/35

  6. Weedman et al. 2005 6/35

  7. Weedman et al. 2005 7/35

  8. Buchanan et al. 2006 Also read: poster by Rajesh et al. -> talks by Hao, Ogle 8/35

  9. The slope of the continuum Sturm et al. 2000 Weedman et al. 2005 Sturm et al. 2006, Rupke et al. 9/35

  10. IR-bright LINERs IR-faint LINERs Sturm et al. 2006 Rupke et al., in prep. Selection based on Ho et al. 1997, Satyapal et al 2003, Veilleux et al. 1995 10/35

  11. Decreasing Type2 fraction with increasing luminosity? SDSS Simpson et al. 2005 11/35

  12. Lutz et al. 2004 Sturm et al. 2006 12/35

  13. II) Silicates 13/35

  14. QUEST (Veilleux et al.) Schweitzer et al. 2006 14/35

  15. Silicate emission in Type 2 objects! NGC 4725: Type 2 AGN from Ho sample (SINGS data, Kennicutt et al.) QSO2s: Sturm et al. 2006 IRASF10214+4724: Teplitz et al. 2006 15/35

  16. ? AGN Silicate emission – where from? The simplest cartoon Silicate emitting dust Radius: ~200 L460.5pc Dust outside sublimation Radius: > ~0.5 L460.5pc 17/35

  17. ? AGN Silicate emission – where from? The simplest cartoon Silicate emitting dust Radius: ~200 L460.5pc Dust outside sublimation Radius: > ~0.5 L460.5pc 18/35

  18. Silicate emission – where from? Dullemond et al. 2001, 2004 Similar Galactic SEDs: flared, passive irradiated protostellar disks … but of course cannot be scaled simply! 19/35

  19. Silicate emission – where from? One alternative cartoon Shi et al. 2006 20/35

  20. Silicate emission – luminosity dependent? Silicate emission observed also at lower luminosity NGC 3998 (Liner 1.9), Sturm et al. 2005 Finding silicate around weaker AGN or, e.g., in ULIRGs is more difficult due to PAH “contamination” Schweitzer et al. 2006 21/35

  21. Silicate emission – the Torus? • Sizeable population of Type 1 AGN with silicate emission • Incidence as a function of luminosity and other factors still under investigation • Demonstrates presence of a significant component of optically thin silicate dust • Is this the “unified” silicate emission from the torus? • Cold Temperatures ~140K-220K (from feature ratio and ISM silicate emissivity profile). Too cold for inner side of torus near sublimation but ok for dust further out, e.g. in the NLR? • emission also in Type II objects 22/35

  22. AverageQSO SED: three mid-infrared bumps 3m bump – 1000-1500K Two silicate bumps QUEST 23/35

  23. IntrinsicQSO SED Netzer et al. (in prep) 24/35

  24. III) PAHs (Polycyclic Aromatic Hydrocarbons) 25/35

  25. 26/35

  26. PAHs in Quasar host galaxies QUEST (Veilleux et al.) Schweitzer et al. 2006 27/35

  27. Average spectra: PAH is widespread Schweitzer et al. 2006 28/35

  28. The origin of QSO far-infrared emission Sanders et al. 1989: warped disk could provide enough cold but AGN-heated dust Rowan-Robinson (1995) pure AGN SED – strong far-infrared then must be star formation 29/35

  29. The origin of the far-IR emission in QSOs (Starburst-AGN connection) Schweitzer et al. 2006 30/35

  30. The origin of the far-IR emission in QSOs (Starburst-AGN connection) • Widespread presence of PAH emission in z<0.3 PG QSOs indicating the presence of powerful starburst activity (νLν60 ~ 2x1010 … 2x1012 L_sun) • Far-infrared emission in QSOs arises mostly from star formation • The star formation environments in the QSO hosts are very similar to ULIRGs • Star formation activity and AGN luminosity correlate up to high luminosity, and starbursts and AGN phase coexist 31/35

  31. PAHs in LINER host galaxies Sturm et al. 2006 Rupke et al., in prep. IR-bright LINERs IR-faint LINERs Selection based on Ho et al. 1997, Satyapal et al 2003, Veilleux et al. 1995 32/35

  32. Mid-Infrared diagnostics of LINERs Sturm et al 2006, Rupke et al. (in prep.), SINGS (J.D. Smith et al., in prep.) cp. Hony et al. 2001 (HII regions, YSOs, evolved stars) cp. Cesarsky et al. 1998, Pagani et al 1999 (star forming regions in M31) 33/35

  33. Appilication at high redshift Same methods can now be applied at high redshifts z~2.8 SMG from Lutz et al. 05 Yan et al. 2005, Houck et al. 2005, Lutz et al. 2005, Weedman et al. 2005b, Desai et al. 2006, Valiante et al. 2006, etc. z~1.3 ULIRG from Desai et al. 06 34/35

  34. Summary Continuum shape (flux ratios 15/6 and 30/6): tool to distinguish AGN types? Continuum ratio mid-IR/X-ray: unification, luminosity dependence of TypeII/TypeI? Silicates: unification (Torus and/or extended emission?) Silicates: luminosity dependence? Crystallization? Grain size distribution? PAHs in QSOs: host galaxy diagnostic PAHs in QSOs: origin of far-IR continuum PAHs in LINERs: tool to distinguish LINER types at high redshift? Continuum + silicates + PAHs: tool to analyse high redshift dusty galaxies Continuum + silicates + PAHs: tool to study AGN evolution 35/35

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