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?.
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Or, how do the BLR properties change with luminosity, and what is it telling us?
The BLR radius vs. luminosity
The BL profiles vs. luminosity
Objects without a BLR.
Is it luminosity dependent?
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)
~15 year of reverberation mappings
Kaspi et al. (2005)
The lowest luminosity type 1 AGN
NGC 4395 should have a tiny BLR, ~ 1 light hour
Moran et al. (1999)
normal line + continuum emission
CoIs - Ho, Filippenko, Maoz, Moran, Peterson, Quillen
April 10-11th 2004 (Desroches et al. 2006)
Lick + Wise
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
Peterson et al. (2005)
Kaspi et al. (2006)
RBLRL1/2 established over a range of ~106(!) in L
Why does RBLRL1/2?
Netzer & Laor (1993)
Dust suppression of line emission.
Line suppression for U>0.01
BLR is dust bounded
BLR IR cont’ NLR
Inevitable & no free parameters
Suganuma et al. (2006)
BLR is bounded by dust sublimation
Applies over a range of 106 in L
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)
Scoville & Norman (1995)
Zurek et al. (1994)
Capriotti et al. (1981),
Stellar tidal disruption
Bogdanovic et al. (2004)
Discrete clouds fluctuations
Profile smoothness limit on nc
L5100Å=6×1045 ergs s-1
L5100Å=7×1042 ergs s-1
Dietrich et al. (1999)
Arav et al. )1998(
No real fluctuations detected
Bloated stars ruled out- for pure thermal broadening
Observelowest L AGN
L5100Å=6×1039 ergs s-1
Rstar~1014 cm - fixed
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
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?
Keck II ESI spectra
Barth et al. (2004)
S/N~50-400 per pixel (0.26Å)
Probe far wings to 10-3
of peak flux density
Symmetric exponential wings
Thermal electron scattering
Wing slope set byTe andτe
Rybicki & Lightman: Radiative Processes in Astrophysics
No wings in NLR
Typical parameters of the BLR gas
A new tool for monitoring Te and τein the BLR
NGC 4395, Pox 52 – very rare objects, MBH~105Msun
What do we expect forMBH~107-109Msun?
Low luminosity AGN should showbroaderlines
How broad do the lines get?
The distribution ofHb line widths
Véron-Cetty et al. (2001)
V2MBH L-1/2 +V<25,000 km s-1
BLR disappears at
True type 2 AGN
Explains absence of BLR in FR Is
1. Real limit. Why does it exist?
2. Detection limit?
(e.g. Nicastro et al.)
Need a BLR survey in very low L AGN
NGC 4450, Ho et al. (2000)
NGC 4203 Shields et al. (2000)
NGC 4579 Barth et al. (2001)
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
Liners (low L/LEdd)
Seyferts (high L/LEdd)
NLR is BH dominated in low luminosity AGN
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?