The mid-IR spectra of AGNs near and far Lei Hao Cornell University

2 Low resolution modules (SL,LL) Low resolution modules (SL,LL) 5-40m wavelength coverage5-40m wavelength coverage Resolution: Resolution: High resolution modules (SH, LH) High resolution modules (SH, LH) 9-38m wavelength coverage9-38m wavelength coverage Resolution: 600Resolution: 600 Spitzer Infrared Spectragraph (IRS)

3 Silicate features PAH emissions Mid-IR spectra examples

4 Silicate Features expected from the unification model Silicate absorption Silicate emission Seyfert2s, Type II Seyfert1s, Quasars, Type I Narrow emission linesBroad emission lines

5 AGN mid-IR spectra ULIRGs quasars

6 Seyfert1Seyfert2 AGN mid-IR spectra

7 Spitzer archival available, complete Spitzer archival available, complete low-res spectra, z<0.5 low-res spectra, z<0.5 Optical classification adopted from Veron-Cetty & Veron (2006)Optical classification adopted from Veron-Cetty & Veron (2006) 24 quasars (3 ULIRGs), 45 Seyfert 1s (7 ULIRGs), 47 Seyfert 2s (8 ULIRGs) and 98 ULIRGs.24 quasars (3 ULIRGs), 45 Seyfert 1s (7 ULIRGs), 47 Seyfert 2s (8 ULIRGs) and 98 ULIRGs. A sample of local AGNs and ULIRGs

8 Mid-IR average spectra Mid-IR average spectra Hao et al., 2006, ApJL, submitted

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

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11 Clumpy unification: The probability of Seyfert 1s showing SA is larger than the probabilities of Seyfert 2s showing SE. Torus opening angle, optical depth, cloud density, dust composition, etc. Hao et al., 2006, ApJL, submitted SE SA -0.4<S 10 < <S 10 <0.3 -1<S 10 <0 -4<S 10 <0.3

12 Extreme IR/opt: probing high- redshift dusty sources IRS was designed to determine redshifts for dusty sources. IRS was designed to determine redshifts for dusty sources. Extreme IR/opt:f (24m)/f (R)>40 Extreme IR/opt:f (24m)/f (R)>40 IRS follow-up for 58 sources from Bootes field and 18 sources from FLS.IRS follow-up for 58 sources from Bootes field and 18 sources from FLS. 57/76 have redshift determined from silicate absorption (53/57) or PAH emission (4/57)57/76 have redshift determined from silicate absorption (53/57) or PAH emission (4/57) Z~2.2Z~2.2 L 6m >10 12 L ๏L 6m >10 12 L ๏ Houck et al., 2005; Desai et al., 2006; Weedman et al., 2006; Higdon et al., in prep

13 Extreme IR/opt: probing high- redshift dusty sources Filled circles: quasars Open circles: ULIRGs Squares: Seyfert1 Crosses: Seyfert2

14 Z~2: ~20% have no apparent silicate absorption, S 10 >-0.3 Shallower than local ULIRGs

15 Conclusion A large sample of local AGNs and ULIRGs with Spitzer IRS observations. A large sample of local AGNs and ULIRGs with Spitzer IRS observations. Quasars are dominated by silicate emission, Seyfert 1s equally by emission and weak absorption, Seyfert 2s by weak absorption, ULIRGs by deep absorption. Quasars are dominated by silicate emission, Seyfert 1s equally by emission and weak absorption, Seyfert 2s by weak absorption, ULIRGs by deep absorption. Local ULIRGs are a similar population as the high-z extreme IR/opt sources, with lower luminosity and somewhat deeper absorption. Local ULIRGs are a similar population as the high-z extreme IR/opt sources, with lower luminosity and somewhat deeper absorption.

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17 Quasars: no silicate emission before Spitzer Roche et al Rigopoulou et al. 1999

18 Hao et al. 2005c, ApJ, 625, L75 See also Siebenmorgen et al. 2005, Sturm et al., 2005 Quasars: silicate emission

19 Type ISilicate emission (SE) Type IISilicate absorption (SA) Type ISE, flat, self-absorbed SE, SA Type IIWeak SA, flat, SE Expected: Observed: AGN dusty structure is very complicated

20 Baldwin Effect in the mid-IR Anti-correlation between the EW of a line and the continuum in AGNs. (Baldwin 1977) Anti-correlation between the EW of a line and the continuum in AGNs. (Baldwin 1977)

21 Baldwin Effect in the mid-IR Keremedjiev & Hao, in preparation