1. Tom Esposito Astr 278 2012 Feb 09

2. Seyfert 1, Seyfert 2, QSO, QSO2, LINER, FR I, FR II, Quasars, Blazars, NLXG, BALQ…

3. 1. All AGN are intrinsically the same and we are just viewing them differently OR 2. Each type of AGN is a distinct phenomenon OR 3. Some combination of 1 and 2

4. Radio-quiet Seyfert 1 Seyfert 2 QSO QSO2 LINERs? Radio-loud FR I, FR II Quasars Blazars Unified Model

5. All radio-quiet AGN have the same central engine Credit: C. M. Urry and P. Padovani  Supermassive black hole + hot accretion disk at center

6. BLR gas excited by UV photons emits broad optical lines  Supermassive black hole + hot accretion disk at center  Hot, high velocity, dense gas clouds near BH form broad-line region

7. Dust & gas torus may obscure central regions of AGN  Supermassive black hole + hot accretion disk at center  Hot, high velocity, dense gas clouds near BH form broad-line region  Compton-thick dusty torus surrounds engine and broad-line region

8. Hot electrons outside torus and BLR scatter nuclear emission  Supermassive black hole + hot accretion disk at center  Hot, high velocity, dense gas clouds near BH form broad-line region  Compton-thick dusty torus surrounds engine and broad-line region  Hot electrons scatter polarized continuum + broad-line emission

9. Narrow emission lines from gas within ionization cones  Supermassive black hole + hot accretion disk at center  Hot, high velocity, dense gas clouds near BH form broad-line region  Compton-thick dusty torus surrounds engine and broad-line region  Hot electrons scatter polarized continuum + broad-line emission  Cool, low velocity, low density gas clouds beyond torus edge form narrow-line region

10. Seyfert 2 Seyfert 1

11.  Featureless optical/UV continuum, soft and hard x-rays from nucleus  Broad permitted optical emission lines  Narrow permitted and forbidden emission lines  IR emission from dust reprocessing of nuclear light

14.  NGC 1068 shows Type 2 spectrum overall but Type 1 spectrum in polarized light (Antonucci & Miller 1985)  Electrons polarize and scatter nuclear emission and broad emission lines into observer’s line-of- sight. O

15.  Molecular gas in torus with 10 24 cm -2 < N H < 10 25 cm -2 absorbs only low energy x-rays  Short-period variability of x-ray absorption implies torus inner edge < 1 pc from nucleus and no more than 10 pc in radial extent (Risaliti et al. 1999, 2002, 2005)  Fe K-α line reflection requires a mirror

16.  Lack of QSO2’s matches prediction of large torus opening angle at high luminosities  Requires AGN to have different-sized tori, which is a modification of the standard unified model  Clumpy torus models can explain mid-IR SED’s of Type 2 AGN  But is a clumpy torus still the Unified Model???

17. Chris Reynolds

18.  Recent efforts to reproduce mid-IR observations of Type-1 and Type-2 Seyferts by Almeida et al. 2011 used clumpy torus models  They found more dependence on torus morphology than inclination  Type-2’s have broader, clumpier, more opaque tori  Does this matter much to the Unified Model?

19.  Unified Model asserts that differences between Type 1 and Type 2 AGN are due to viewing angle only!  Optical/UV, IR, and x-ray observations support this model to a degree  Radio-loud AGN are unified with similar scheme to radio-quiet but with less certainty

20.  Obscuring torus blocks broad lines in Type 2’s  1-several pc (based on x-rays) (or 100+?? Based on IR) scale radially, 0.1-1 pc vertically  Inner edge defined by dust sublimation temp  N H > 10 24 cm -2  Type 2 continuum is also weaker than Type 1  Warm electrons scatter and polarize featureless continuum light from nuclear region in Type 2’s  Matches Type 1’s except polarized  Antonucci & Miller 1995  spectropolarimetry

21.  Torus dust absorbs optical broad lines along direct line of sight to observer  Often assumed coaxial with BH spin axis – ang momentum conservation  Line emission aimed out of torus plane gets scattered towards observer in polarized light  Near-IR broad line emission passes through torus more easily than optical  Torus is only geometrically wide enough to obscure broad line region and not narrow line region  High equivalent width Fe K-α line observed in Type 2’s – direct x-ray photons absorbed by Compton thick medium; observed weak continuum and iron line is reflected off that medium  Narrow line region should have bi-conical shape based on opening angle of torus – observed with high-resolution HST imaging (Pogge 1998, Barbosa et al. 2009)  Axis of cones often slightly misaligned with minor axis of host galaxy and radio jets – torus and central engine misaligned

22.  Torus often modeled as smooth mix of gas and dust – difficulty in keeping torus geometrically thick (puffy)  Idea of thin disk tilted or warped  Models recently of clumpy medium ▪ Supported by recent x-ray observations, as Robin will discuss ▪ Also by broad IR SED – needs either huge torus (100 pc; not observed) or clumpy medium ▪ Nenkova et al. 2002, 2008 mostly successful in reproducing mid-IR observations with clumps (if smooth, dust would be destroyed too quickly by hot surrounding gas, Krolik & Begelman 1988)