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AGN Unification Viewed in the mid-IR

AGN Unification Viewed in the mid-IR . Spectra. Lei Hao Cornell University. Broad emission lines. Seyfert1s, Quasars, Type I. Silicate dust emission. Narrow emission lines. Seyfert2s, Type II. Silicate dust absorption. Why Mid-IR. Dust in ISM: oxygen-rich silicates

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AGN Unification Viewed in the mid-IR

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  1. AGN Unification Viewed in the mid-IR Spectra Lei Hao Cornell University

  2. Broad emission lines Seyfert1s, Quasars, Type I Silicate dust emission Narrow emission lines Seyfert2s, Type II Silicate dust absorption Why Mid-IR • Dust in ISM: • oxygen-rich silicates • carbon-rich grains

  3. Broad emission lines Seyfert1s, Quasars, Type I Silicate dust emission Narrow emission lines Seyfert2s, Type II Silicate dust absorption Why Mid-IR • Low resolution modules (SL,LL) • 5-40m wavelength coverage • Resolution: 64-128 • High resolution modules (SH, LH) • 9-38m wavelength coverage • Resolution: 600 • Dust in ISM: • oxygen-rich silicates • carbon-rich grains

  4. QSO Seyfert Si-O stretching O-Si-O bending ULIRG Starburst Silicate features Mid-IR spectra examples

  5. AGN mid-IR spectra quasars ULIRGs

  6. AGN mid-IR spectra Seyfert1 Seyfert2

  7. A sample of local AGNs and ULIRGs • Spitzer archival available, complete low-res spectra, z<0.5 • Optical classification adopted from Veron-Cetty & Veron (2006) • 24 quasars (3 ULIRGs), 45 Seyfert 1s (7 ULIRGs), 47 Seyfert 2s (7 ULIRGs) and 98 ULIRGs.

  8. Mid-IR average spectra Hao et al. 2007, ApJ, 655, L77

  9. Mid-IR average spectra (Brandl et al., 2006)

  10. SE SA • Deep silicate absorption in ULIRGs Hao et al. 2007, ApJ, 655, L77

  11. Silicate features in Seyferts are week Deo et al. 2007, /0709.3076/

  12. SE SA • Many Seyfert 1s show absorptions: • Clumpy unification • Host galaxy contamination • The probability of Seyfert 1s showing SA is larger than the probabilities of Seyfert 2s showing SE. Hao et al. 2007, ApJ, 655, L77

  13. SE SA • Silicate features in Quasars are mainly in emission Hao et al. 2007, ApJ, 655, L77

  14. Maiolino et al. 2007, A&A, 468 979

  15. Hao et al. 2005c, ApJ, 625, L75 See also Siebenmorgen et al. 2005, Sturm et al., 2005 Silicate features in AGN • We finally detected the emission feature in QSOs. • Caution: does the emission come from the torus or host galaxies? • Emission vs. absorption for Type I and Type II are clearer for high-luminosity AGN. • Seyferts have weak silicate features, many Seyfert 1s have silicate absorptions.

  16. QSO Seyfert ULIRG Starburst PAH (Polycyclic Aromatic Hydrocarbon)emissions (C-H and C-C stretching and bending modes) Mid-IR spectra examples

  17. PAH strength trace the Starformation in the hosts Weedman, et al. 2005

  18. Unification: Type I and Type II AGN should have comparable PAH strength.

  19. Mid-IR average spectra (Brandl et al., 2006)

  20. Mid-IR average spectra • PAH emissions are stronger in Seyfert 2s than in Seyfert 1s • Similar in Buchanan et al. (2006) and Deo et al. (2007) • Need a control sample

  21. PAH stronger in Seyfert 2s? • Over 60 optically selected Seyfert 1s and Seyfert 2s sampled over their [OIII] luminosities. Seyfert 2s Seyfert 1s Hao et al., in preparation

  22. QSO Seyfert ULIRG Starburst Mid-IR spectra examples

  23. Since IR is less sensitive to extinction, Then, Unification: Type I and Type II AGN have comparable IR emission line properties?

  24. Dudik et al. 2007 Deo et al. 2007 Mid-IR atomic emission lines • Deo et al. (2007): Seyfert 1s have stronger [OIV]25.89/[NeII]12.81, [NeIII]15.56/[NeII]12.81, and [NeV]14.32/[NeII]12.81 than Seyfert 2s. • Enhanced [NeII] emission in Seyfert 2s? • Dudik et al. (2007): Seyfert 2s have lower [NeV]14.3/[NeV]24.3 ratios than Seyfert 1s: extinction to [NeV] emitting region?

  25. Conclusion • Mid-IR spectrum is a power tool in testing and constraining the unified view of AGN: silicate features, PAH emissions, atomic lines, continuum… • In general, the observations support type II AGN have more obscuration. • But the dust structure in AGN is more complicated.

  26. Conclusion • Mid-IR spectrum is a power tool in testing and constraining the unified view of AGN: silicate features, PAH emissions, atomic lines, continuum… • In general, the observations support type II AGN have more obscuration. • But the dust structure in AGN is more complicated.

  27. Conclusion • Mid-IR spectrum is a power tool in testing and constraining the unified view of AGN: silicate features, PAH emissions, atomic lines, continuum… • In general, the observations support type II AGN have more obscuration. • But the dust structure in AGN is more complicated.

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