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Tom Esposito Astr 278 2012 Feb 09. Seyfert 1, Seyfert 2, QSO, QSO2, LINER, FR I, FR II, Quasars, Blazars, NLXG, BALQ…

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Presentation on theme: "Tom Esposito Astr 278 2012 Feb 09. Seyfert 1, Seyfert 2, QSO, QSO2, LINER, FR I, FR II, Quasars, Blazars, NLXG, BALQ…"— Presentation transcript:

1 Tom Esposito Astr 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

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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 cm -2 < N H < 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 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, pc vertically  Inner edge defined by dust sublimation temp  N H > 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)


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