1. What can we learn on the BLR from the smallest AGN? Or, how do the BLR properties change with luminosity, and what is it telling us? Specifically The BLR radius vs. luminosity The BL profiles vs. luminosity Objects without a BLR.

2. The AGN Paradigm Is it luminosity dependent?

3. Weak luminosity dependence Ionization level and density are ~ constant Ionizing flux at the BLR~ constant R BLR  L 1/2 How far down in L does R BLR  L 1/2 holds? The Baldwin relation C III] Lyα C IV O VI Laor et al. (1995) Baskin & Laor (2004)

4. The R BLR vs. L relation ~15 year of reverberation mappings Kaspi et al. (2005) ? NGC 4395 The lowest luminosity type 1 AGN L 10 39 ×6= (Å5100) ? NGC 4395 should have a tiny BLR, ~ 1 light hour

5. NGC 4395

6. NGC 4395 – The lowest luminosity type 1 AGN normal line + continuum emission L bol ~10 40 erg/s, But C III ] HeII O III] C IV Moran et al. (1999)

7. Reverberation mapping campaign on NGC 4395 (2004, 2006) HST Chandra Lick + Wise April 10-11th 2004 (Desroches et al. 2006) CoIs - Ho, Filippenko, Maoz, Moran, Peterson, Quillen

8. What is The size of the BLR ? The C IV time delay is: Peterson et al. (2005) 48±20 min in visit 2, 66±20 min visit 3 The most compact BLR known

9. The R BLR vs. L Relation for C IV + Kaspi et al. (2006) R BLR  L 1/2 established over a range of ~10 6 (!) in L Peterson et al. (2005)

10. Why does R BLR  L 1/2 ? Dust suppression of line emission. Theory Netzer & Laor (1993) BLR IR cont’ NLR Σ ion =10 23 U, U=n γ /n e     IR Lines Dusty gas  Dust = Σ/10 21 =100U Line suppression for U>0.01 Dust sublimation. R sub ≤0.2L 46 1/2 pc BLR is dust bounded Inevitable & no free parameters

11. IR reverberation Observation Suganuma et al. (2006) BLR is bounded by dust sublimation Applies over a range of 10 6 in L Dust BLR Dust

12. What are the BLR “Clouds”? In photoionized gas: Σ ion =10 23 U, U=n γ /n e in the BLR: n e ~10 10, U~0.1 Σ ion =10 22 The thickness of the photoionized layer is d~10 12 cm >>R BLR ~10 16 -10 17 cm in luminous AGN The BLR gas filling fraction is 10 -5 -10 -6 A smooth flow? (e.g. disk ablation) A clumped flow? (e.g. bloated stars)

13. The BLR “clouds”=A stellar origin? Bloated stars Stellar contrails Star-disk interactions Kazanas (1989) Scoville & Norman (1995) Zurek et al 

14. Implied emission line profiles Stellar tidal disruption Discrete clouds fluctuations Profile smoothness limit on n c Capriotti et al. (1981),1981 n c 100= n c 500= n c 1000=n c 2000= n c 5000=n c 10000=  xample: Bogdanovic et al. (2004)

15. How smooth are the broad lines? NGC 41513C 273 No real fluctuations detected Bloated stars ruled out- for pure thermal broadening L 5100Å = 7×10 42 ergs s -1  L 5100Å = 6×10 45 ergs s -1 Dietrich et al. (1999)1999 Arav et al. )1998(1998 r cloud ≈R BLR /)n c ( 1/2 Observe  lowest L AGN

16. What do we see in the smallest AGN? R star ~10 14 cm - fixed while R BLR  L 1/2 Lowest L AGN should show the largest fluctuations NGC 4395 In NGC 4395 R BLR ≈   cm  R star L 5100Å = 6×10 39 ergs s -1 Laor, Barth, Ho &Filippenko (2006 ) -  eck spectra No room for bloated stars

17. Bloated stars are ruled out conclusively r cloud <10 12 cm = thickness of the photoionized layer BLR gas is in a smooth flow, probably a thick disk Why are the line profiles not always double peaked?

19. What else can we learn from the line profiles? Barth et al.  S/N~50-400 per pixel (0.26Å) Keck II ESI spectra

20. Exponential extended wings in H  Laor (2006) Probe far wings to 10 -3 of peak flux density Symmetric exponential wings NGC 

21. What produces exponential wings? Wing slope set by T e and τ e Thermal electron scattering Rybicki & Lightman: Radiative Processes in Astrophysics

22. What are the implied T e and τ e ? No wings in NLR Typical parameters of the BLR gas A new tool for monitoring T e and τ e in the BLR

23. BLR profiles in low Luminosity AGN NGC 4395, Pox 52 – very rare objects, M BH ~10 5 M sun What do we expect for       M sun ? V 2 ≈GM BH /R BLR  M BH / L 1/2 Low luminosity AGN should show broader lines How broad do the lines get?

24. Véron-Cetty et al.  The distribution of  H  line widths Vmax~20,000 km/s 1. Real limit. Why does it exist? 2. Detection limit? L Edd Implications: V 2  M BH L -1/2 +V<25,000 km s -1 BLR disappears at L<10 25.8 M BH 2 or L/LEdd<10 -12.3 M BH True type 2 AGN upper limit Explains absence of BLR in FR Is

25. What controls the existence of the BLR? V>20,000 BLR Dusty gas L/L Edd Need a BLR survey in very low L AGN Option 1: Option 2: Laor (2003) (e.g. Nicastro et al.)

26. NGC 4450, Ho et al. (2000) NGC 4203 Shields et al. (2000) NGC 4579 Barth et al. (2001) Low Luminosity AGN with very broad lines

27. What happens to the NLR at very low L? Compact BLR compact NLR enters the BH potential well Example: [O III] 5007, 4959 Emissivity maximized at n e ~10 6, U~10 -3 n    vs.  n  =10 9 in BLR R [O III] ~10 3 R BLR (for the most compact  region)      BLR  M BH 1/4 (L/L Edd )-1/4 km/s What is the critical luminosity for BH dominance? The bulge contribution is:      km/s   Tremaine et al.   [O III]/  *  0.15(L/L Edd )-1/4 BH dominates when L/L Edd <5x10 -4

28.  Veilleux (1991) L/L Edd ~1 L/L Edd =5x10 -5 BH dominated Bulge dominated NLR in: Liners (low L/L Edd ) Seyferts (high L/L Edd ) NLR is BH dominated in low luminosity AGN

29. Some open questions What is the threshold parameter for the existence of a BLR? (maximal velocity, L/L Edd ) (is the BLR in a thick disk? how is it supported?) What is the velocity field of the BLR? How significant are non-gravitational forces? (explain profile asymmetries?) Where does the BLR come from, and where does it go to?