What I learned during my Xian Vacation

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What I learned during my Xian Vacation
Essay

• Joe Shields
• Ohio University

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To make sense of it all we just need to
understand
DUST
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Reasons to pay attention to dust

• Dust central to understanding the torus
• - its small, but resolved (Jaffe, Davies)
• - its clumpy (Elitzur, Hoenig poster, )
• - it defines the boundary of the BLR (Laor,
  Suganuma)

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Lag time vs. Optical Luminosity with BLR lags
NIR(K-band)
Broad Emission Line
F9 Clavel et al. (89)
Rodriguez-Pascual et al. (97)
Peterson et al. (04) N3783 Reichert et al.
(94) N7469 Wanders et al. (97)
Kriss et al. (00) Collier et al.
(98) N5548 Peterson et al. (02)
Krolik et al. (1991) Peterson
Wandel. (99) Dietrich et al. (93)
Korista et al. (95) N4151 Clavel
et al. (90) Maoz et al. (91)
Kaspi et al. (96)

• Broad-emission line lags for objects that also
  have infrared lags
• Including Hi Lo ionization lines)

(nucleus)
N3227 Winge et al. (95) Onken et
al. (03) Shemmer et al. (04)
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Reasons to pay attention to dust

• Dust explains why Seyfert 2s exist
• - obscuration of BLR as a function of
  orientation
• - disappearance of BLR at low luminosity?
• (Elitzur, related to wind Laor related to
  inner radius)

• N.B. Remember Ed Morans cautionary words
  regarding
• incidence of hidden broad-line regions
• - strong selection/sensitivity effects (but
  getting better)
• - absence of evidence ? evidence of absence
• - lack of x-ray absorption is not diagnostic

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Reasons to pay attention to dust
3. Its an essential part of the NLR - radiation
pressure on dust determines ionization
structure? (Groves) (complications star
formation, jets - Bennert, Holt, Inskip)

• Its an important constraint on early star
  formation
• associated with AGNs (Hamann)

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Ways to probe dust in AGNs

• IR Spectroscopic features (A. Lee, Sturm, Hao,
  Deo poster)
• 9.7 ?m feature
• PAHs

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Mid-IR average spectra
(Brandl et al., 2006)
L. Hao talk
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Ways to probe dust in AGNs

• IR Spectroscopic features (A. Lee, Sturm, Hao,
  Deo poster)
• 9.7 ?m feature
• PAHs
• XAFS in x-ray spectra (J. Lee)
• Extinction/reddening law (Czerny) !!!!
• Unification tests
• - Radio galaxies quasars (Cleary, Lal, Schulz
  poster)

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What Dust Cannot Explain

• The X-ray absorber in Seyfert 1s
• - x-ray absorber ? infrared absorber (Elitzur,
  )
• - located on scale similar to BLR (Maiolino)
• mid-IR emission much more extended
• - selection effects an issue at high NH
• Opportunities for study
• - time-variability (Risaliti)
• - fossil reflection (Maiolino)
• - XRB constraints for Compton-thick sources

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What Dust Cannot Explain
2. Differences between Seyferts and LINERs -
amazing dichotomy in BPT diagrams! (Groves)
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Sweet Separation
Brent Groves -NLR Models
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What Dust Cannot Explain
2. Differences between Seyferts and LINERs -
amazing dichotomy in BPT diagrams! (Groves) -
probable explanation different SEDs (Ho) - SEDs
really are different - lack of blue bump in
LINERs not extinction - see some LINERs as
UV sources (Elitzur quoting Maoz) - at low z,
MBH different (Constantin, Greene) - low L/Ledd
? ADAF or RIAF in LINERs
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What Dust Cannot Explain
2. Differences between Seyferts and LINERs -
amazing dichotomy in BPT diagrams! (Groves) -
probable explanation different SEDs (Ho) - SEDs
really are different - lack of blue bump in
LINERs not extinction - see some LINERs as
UV sources (Elitzur quoting Maoz) - at low z,
MBH different (Constantin, Greene) - low L/Ledd
? ADAF or RIAF in LINERs Tools to probe
excitation/energetics - X-ray (Marquez) -
point sources in many cases, not always - IR
lines (Chary, Rupke)
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Other New Things

• A new composite QSO spectrum (Shang)

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Results 1 of 3 Spectral Energy Distributions

• Our sub-sample of 15 objects
• Composite spectrum (UV optical mid-IR)
• Normalized at 5600 Å
• Clear Silicates features around 10 and 18 µm

• Near-IR composite spectrum (Glikman et al. 2006)
• 27 AGNs (zlt0.4)
• 1 micron inflexion

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Other New Things

• A new composite QSO spectrum (Shang)
• Clustering constraint on Seyfert companions (C.
  Li)

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C. Li talk
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Other New Things

• A new composite QSO spectrum (Shang)
• Clustering constraint on Seyfert companions (C.
  Li)
• High-velocity HI absorption wings - tracer of
  feedback
• (Morganti)
• Do star formation indicators break down in
  presence
• of luminous AGN? E.g. OII, PAHs (Levenson)
• IMF on small scales may be skewed to high masses
• (Nayakshin) - does this remove observable
  signatures
• for t ? 108 yrs? (Cf. Sarzi)

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Other New Things

• New metallicity diagnostics for the NLR (Nagao)
• M-sigma deviations at z0.37 (Malkan)
• New tidal disruption candidates (Gezari)

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Homework A to-do list

• Clean up statistics on Sey 1/Sey 2 incidence ?
• (Elitzur, Martinez-Sansigre)
• (Moshe Clumpy unification becomes an issue of
  probability)
• N.B. dont expect ratios to be same in Optical
  and X-ray

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Clumpy Unification
0
Nc(?) N0 exp(-?2/?2)
AGN type is a viewing-dependent probability!

• Type 1 sources from type 2 viewing, and vice
  versa
• Flips between type 1 2 (Aretxaga et al 99)
• f2 variations may arise from either ? or N0 or
  both

f2 depends on both ? and N0!
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A to-do list

• Clean up statistics on Sey 1/Sey 2 incidence ?
• (Moshe Clumpy unification becomes an issue of
  probability)
• Revisit X-ray absorption vs. Luminosity? (J.X.
  Wang)
• Figure out why bars are associated with higher
  x-ray NH
• (Maiolino)
• Be worried about studies that use jet axis as an
  indicator
• of torus/disk axis (Jaffe)

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Jaffe talk - NGC 1068
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A to-do list

• Clean up statistics on Sey 1/Sey 2 incidence ?
• (Moshe Clumpy unification becomes an issue of
  probability)
• Revisit X-ray absorption vs. Luminosity? (J.X.
  Wang)
• Figure out why bars are associated with higher
  x-ray NH
• (Maiolino)
• Be worried about studies that use jet axis as an
  indicator
• of torus/disk axis (Jaffe)
• Find more objects suitable for time-variability
  studies of
• x-ray absorption (Risaliti)

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A to-do list (continued)

• 6. Start thinking about consequences of
  reflection of optical
• light from torus (Gaskell)
• 7. Worry more about aperture effects (Jaffe,
  Sturm, Prieto, )
• 8. Gain some more insight into extinction/reddenin
  g law !
• 9. Look for time variability in Si 9.7 ?m feature
  (Gaskell/Ogle)
• Measure metallicities in high-z, low-L AGNs to
  address evolutionary issues (Nagao)

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A to-do list (continued)
11.Start thinking time-domain science (LSST,
EXIST) and other opportunities with new missions
Last but not Least
Make plans to visit China again!
-The End-