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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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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
The AGN Paradigm

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)

Lyα

O VI

C IV

C III]


The r blr vs l relation
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



Ngc 4395 the lowest luminosity type 1 agn
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


Reverberation mapping campaign on ngc 4395 2004 2006
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


What is the size of the blr
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


The r blr vs l relation for c iv
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


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


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


What are the blr clouds
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)


The blr clouds a stellar origin
The BLR “clouds”=A stellar origin?

Kazanas (1989)

Bloated stars

Scoville & Norman (1995)

Zurek et al. (1994)

Star-disk interactions

Stellar contrails


Implied emission line profiles
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


How smooth are the broad lines
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


What do we see in the smallest agn
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


Bloated stars are ruled out conclusively
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?


What else can we learn from the line profiles
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)


Exponential extended wings in h a
Exponential extended wings in Ha

NGC 4395

Laor (2006)

Probe far wings to 10-3

of peak flux density

Symmetric exponential wings


What produces exponential wings
What produces exponential wings?

Thermal electron scattering

Wing slope set byTe andτe

Rybicki & Lightman: Radiative Processes in Astrophysics


What are the implied t e and e
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


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?


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?


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


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)


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


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


Some open questions
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?


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