1. Dusty Torus Formation by Anisotropic Radiative Feedback of Active Galactic Nuclei
Shuang-Nan Zhang, Yuan Liu, Jin Zhang
Institute of High Energy Physics
and
National Astronomical Observatories of China
Chinese Academy of Sciences
Liu,Y. & Zhang, S.N., 2011, ApJL, 728, L44

2. The unified model of AGN
Formation？
Dusty torus
Evolution？

3. AGN feedback The distribution of the dust is anisotropic
The normal of the accretion disk
The distribution of the dust is anisotropic
The UV/optical radiation from the accretion disk is also anisotropic
The effect of radiation pressure is significant due to the presence of dust
Observer & dust
A~500

4. The evolution of AGNs A B C
Momentum effect of radiation

5. Evaporation radius
The inner radius of dust
Energy effect of radiation

6. Torus formation time scale: ~105-6 yr for 10 pc
~0.2 ly
Radiation pressure
1 year
Evaporation
L=1044 erg/s; L/LEdd=0.1; a=0.1 mm; A=100
a：dust radius
Hot low density gas:
Seed for BLR?
Empty
Vertical distance from the disk Z (pc)

7. The profile of a dusty torus

8. NH-L/LEdd plane
Raimundo, Fabian, Bauer et al. 2010

9. The fraction of type 2 AGNs
Hasinger 2008

10. The inner radius of dusty torus
Suganuma et al. 2006

11. The evolution of dusty torus
Luminous, with torus, but without bright BLR
105-6 yr ?
Low
density
gas
High density clouds

12. Weak line quasars
Shemmer et al ; EW<5 A; continuum similar to normal quasars

13. Radio quiet BL Lac
No obvious emission lines
Plotkin et al

14. Are WLQs and Radio Quiet BL Lac the Objects Predicted by Our Model?
Predictions
Luminous accretion disk emission
Existence of Dusty Torus
Tests
Low polarization  disk not jet
Low variability  disk not jet
Hot dust emission  torus illuminated by luminous disk

15. Polarization Test: radio quiet BL Lac
Very low polarization in continuum spectra: only two of 25 candidates are observed with weak polarization (Heidt & Nilsson 2011); non detection for all others
The continuum spectrum is consistent with disk origin

16. Long Term Variability Test
So far observations are quite limited
Weaker than radio loud BL Lac？
Need more observations
Plotkin et al

17. Long Term Variability Test
SDSS Stripe 82（12 radio quiet BL Lac，4 WLQ，27 radio loud BL Lac）
Radio quiet
Radio loud

18. Lightcurve amplitudes
Radio loud
Radio quiet

19. Four SDSS Radio Quiet BL Lac Observed with Lijiang 2
Four SDSS Radio Quiet BL Lac Observed with Lijiang 2.4 m at V, I and R bands
SDSS
SDSS

20. Very weak short timescale variability!
Short Term Variability Test
m(BL Lac)-m(Star)
Time (Hour)
Very weak short timescale variability!

21. Hot Dust Test in weak line quasars
Black body from hot dust
Diamond-Stanic et al. 2009
Evidence of hot dust in WLQ

22. Conclusions
The distribution of dusty gas should also be anisotropic due to the influence of the anisotropic disk radiation.
Our model can explain the presence of some obscured AGNs with high Eddington ratios and can also reproduce the observed decreasing fraction of type 2 AGNs with increasing luminosity.
Our model predicts the existence of luminous AGNs with dusty tori, but without luminous broad line regions.
Weak line quasars and radio quiet BL Lac?
Weak polarization, low variability and hot dust feature confirm our model predictions.
Liu,Y. & Zhang, S.N., 2011, ApJL, 728, L44