1 / 29

What can we learn on the BLR from the smallest AGN?

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. The AGN Paradigm. Is it luminosity dependent?.

sienna
Télécharger la présentation

What can we learn on the BLR from the smallest AGN?

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  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 RBLR L1/2How far down in L does RBLR L1/2 holds? The Baldwin relation Laor et al. (1995) Baskin & Laor (2004) Lyα O VI C IV C III]

  4. The RBLR vs. L relation ~15 year of reverberation mappings Kaspi et al. (2005) NGC 4395 The lowest luminosity type 1 AGN 1039×6= (Å5100) L  ? ? NGC 4395 should have a tiny BLR, ~ 1 light hour

  5. NGC 4395

  6. NGC 4395 – The lowest luminosity type 1 AGN Moran et al. (1999) C IV C III] HeII O III] But Lbol~1040 erg/s, normal line + continuum emission

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

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

  9. The RBLR vs. L Relation for C IV + Peterson et al. (2005) Kaspi et al. (2006) RBLRL1/2 established over a range of ~106(!) in L

  10. Why does RBLRL1/2? Theory Netzer & Laor (1993) Σion=1023U, U=nγ/ne Dust suppression of line emission. Dust= Σ/1021=100U Line suppression for U>0.01 Dust sublimation. Rsub≤0.2L461/2 pc BLR is dust bounded BLR IR cont’ NLR Lines 1021 Dusty gas IR 1022 Inevitable & no free parameters

  11. Observation Suganuma et al. (2006) Dust BLR Dust IR reverberation BLR is bounded by dust sublimation BLR Applies over a range of 106 in L

  12. What are the BLR “Clouds”? In photoionized gas: Σion=1023U, U=nγ/ne in the BLR: ne~1010, U~0.1 Σion=1022 The thickness of the photoionized layer is d~1012 cm >>RBLR~1016-1017 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? Kazanas (1989) Bloated stars Scoville & Norman (1995) Zurek et al. (1994) Star-disk interactions Stellar contrails

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

  15. How smooth are the broad lines? L5100Å=6×1045 ergs s-1 L5100Å=7×1042 ergs s-1 3C 273 NGC 4151 Dietrich et al. (1999) Arav et al. )1998( No real fluctuations detected Bloated stars ruled out- for pure thermal broadening rcloud≈RBLR/)nc(1/2 Observelowest L AGN

  16. What do we see in the smallest AGN? L5100Å=6×1039 ergs s-1 Rstar~1014 cm - fixed NGC 4395 while RBLRL1/2 Laor, Barth, Ho &Filippenko (2006) -Keck spectra Lowest L AGN should show the largest fluctuations In NGC 4395 RBLR ≈ 1014cm~ Rstar No room for bloated stars

  17. Bloated stars are ruled out conclusively rcloud<1012 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?

  18. What else can we learn from the line profiles? Keck II ESI spectra Barth et al. (2004) S/N~50-400 per pixel (0.26Å)

  19. Exponential extended wings in Ha NGC 4395 Laor (2006) Probe far wings to 10-3 of peak flux density Symmetric exponential wings

  20. What produces exponential wings? Thermal electron scattering Wing slope set byTe andτe Rybicki & Lightman: Radiative Processes in Astrophysics

  21. What are the implied Te and τe? No wings in NLR Typical parameters of the BLR gas A new tool for monitoring Te and τein the BLR

  22. BLR profiles in low Luminosity AGN NGC 4395, Pox 52 – very rare objects, MBH~105Msun What do we expect forMBH~107-109Msun? V2≈GMBH/RBLRMBH/L1/2 Low luminosity AGN should showbroaderlines How broad do the lines get?

  23. The distribution ofHb line widths upper limit Véron-Cetty et al. (2001) Implications: LEdd V2MBH L-1/2 +V<25,000 km s-1 BLR disappears at L<1025.8MBH2 orL/LEdd<10-12.3MBH True type 2 AGN Explains absence of BLR in FR Is Vmax~20,000 km/s 1. Real limit. Why does it exist? 2. Detection limit?

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

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

  26. What happens to the NLR at very low L? Compact BLR compact NLR enters the BH potential well What is the critical luminosity for BH dominance? Example: [O III] 5007, 4959 Emissivity maximized at ne~106, U~10-3 ng=103 vs. ng=109 in BLR R[O III] ~103RBLR (for the most compact [O III] 5007, 4959 region) s[O III]~10-1.5sBLR=0.28MBH1/4(L/LEdd)-1/4 km/s The bulge contribution is: s*=1.9MBH1/4 km/s(Tremaine et al. 2002) s[O III]/s*= 0.15(L/LEdd)-1/4 BH dominates when L/LEdd<5x10-4

  27. NLR in: Liners (low L/LEdd) Seyferts (high L/LEdd) (1988) Veilleux (1991) L/LEdd~1 L/LEdd=5x10-5 Bulge dominated Bulgedominated BH dominated NLR is BH dominated in low luminosity AGN

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

More Related