The Radiative Efficiency of Individual AGN

Shane Davis (IAS) & Ari Laor (Technion)

Why is the radiative efficiency (η) important?

Gives the spin (a*), which indicates the accretion history

a*=1 → uniform accretion geometry

a*=0 → independent accretion events

How much mechanical power can go to wind/jet?

What is the disk structure? (is it radiatively efficient, or advection, radiation trapping take place?)

Measuring the Radiative Efficiency (η)

The Soltan argument - ηav/(1- ηav) = total L / total MBH

→ ηav≥0.1 (e.g. Yu & Tremaine 2002; Elvis et al. 2002; Marconit al. 2004; Barger et al. 2005)

Can also estimate ηav(z) and ηav(L), but with a larger uncertainty

In individual AGN Lbol= η × Mdotc2

Can we measure Mdot directly?

For a local BB accretion disk, Newtonian gravity, no edge effects:

Does it works for a relativistic accretion disk (Novikov & Thorne)?

Using an atmospheric model (Hubeny’s TLUSTY)?

Using relativistic radiation transfer (Agol’s KERTRANS)?

Using different black hole spin (a*)?

Using different values of α?

a*=0

a*=0

0.9

0.9

0.998

0.998

Fixed Mdot = changing MBH and a*

If MBH is known, Mdot is fixed by Lν,

Mdot independent of a*

Atmospheric models – BB versus TLUSTY

Optical

A small effect in the optically emitting region

Derived Mdot for 80 PG Quasars

Ratio of Mdot for different a* and atmospheric models

A simple derivation of Mdot

The Results for the 80 Quasars

BLR

σ

What is Lbol fot the PGs ?need it for η=Lbol/Mdotc2

Combine Optical, UV (HST+ FUSE), X-Ray (ROSAT) + extrapolations

The dependence of η on MBH

a*=0.998

a*=0

log(η)= -1 ± 0.3

Additional correlations of η

If η implies a*

Fanidakis et al.arXiv:0911.1128

But why is the SED universal?

Are we missing something fundamental about AD SED ?

Conclusions

η is correlated with MBH

a* is related to MBH , but maybe

very low η due to wind/radiation trapping?

very high η due to what?

What drives the universal SED?

)just an a* - MBH coincidence(?