Silicate Emission in Active Galaxies

Mario Schweitzer

MPE

E. Sturm, D. Lutz, R. Genzel, S. Veilleux, D. Rupke, D.-C. Kim, B. Groves,

D. Tomono, Hagai Netzer

QUESTQuasar And ULIRG Evolution Study

Emission From The Torus Or (And) Extended Emission ???

[OIV]25.89

[NeII]12.81

PAH7.7/8.6

PAH6.2

PAH11.3PAH12.7

F.Molster et al. (2004)

Si-O stretching

Si-O-Si bending

10m Silicate emission in Type 1 AGNOriginal prediction of torus models, but not really observed until very recently…

Suggested modifications to explain absence of silicate emission:- changes of grain size distribution (Laor & Draine 1993, Maiolino et al. 2001)- Special geometries, e.g. tapered disks (Efstathiou & Rowan-Robinson 1995)- Clumpy tori (Nenkova et al. 2002)

Opt. thin dust, different size distributions (Laor & Draine 93)

Type 1 SED for different radial distributions of clumps (Nenkova et al. 02)

0.1 1 10m 100 1000

q : power law exponent for radial clump distribution

ß: power law exponent of size distribution

Siebenmorgen et al. 2005 Hao et al. 2005

Spitzer finally finds silicate emission in luminous AGNs (PG QSOs)

QUEST (Veilleux et al.)

Schweitzer et al. 2006

PG-QSOs (Type 1)

Siebenmorgen et al. 2005

Hao et al. 2005

Conditions in the silicate emitting region

Weingartner & Draine 2001

The Unification model

sublimation temperature between 800 and 1500 K(Kimura et al. 2002)

But estimated temperatures are ~ 200 K too cold

Silicate emission in Type 2 objects!

NGC 4725: Type 2 AGN from Ho sample (SINGS data, Kennicutt et al.)

QSO2s: Sturm et al. 2006

IRASF10214+4724: Teplitz et al. 2006

Silicate emission – the Torus?

possibly spatially extended silicate emission

cold temperatures + silicate emission in type 2

Model the silicate emission

Illuminated cloud models: Brent Groves (MPA)

Modelling silicate emission spatial extension

Dust outside sublimation Radius: > ~0.5 L46

0.5pc

Silicate emitting dustRadius: ~200 L46

0.5pc

?AGN

Dust outside sublimation Radius: > ~0.5 L46

0.5pc

Silicate emitting dustRadius: ~200 L46

0.5pc

?AGN

…and at lower luminosity A testcase for the spatial extension of

the silicate emission regionNGC 3998 (Liner 1.9) Sturm et al. 2005

L (2-10 keV) = 3 x 10 ^41 ergs/s (Ptak et al. 2004)

T~180K(from feature ratio and ISM silicate emissivity profile).

Follow-up SUBARU (COMICS) observation of NGC3998A preliminary result

I11.7

-I8.6

2MASS JHK-band (NED)

image size : 200 pc2

(together with DaigoTomono)

fluxd

en

sity

[Jy

]

C8.6

I

=

I

image size : 200 pc2

MAXI

I

Subtracting the normalized PSF (center images on maximum)

-

PSFstarMAX

PSFstar

I

I 7.11

=

First image of extended (residual) silicate emission in AGN

~35pc

this is a upper limit since no PSF-correction !

D ~ 35 pc

image size : 200 pc2

Using illuminated cloud models from Brent Groves (MPA):

D ~ 30 pc

Conclusions- Silicate emission detected in AGNs over four orders of magnitude in

luminosity. Origin in torus or extended emission ?

- Arguments for extended emission:

1) Estimated temperatures (optical thin) are much lower then the sublimation temperature !

2) Silicate emission has been detected also in type 2 AGNs.

3) For the LINER NGC 3998 we find silicateemission on a scale of D ~ 30 pc (preliminary result)

In addition to more Spitzer spectroscopy, these issues call for very high resolution observations and interferometry!

res. : 0.1´´ (~7 pc)wavelength: 12.5 µm

NGC 1068: ~2/3 of emission extended (overlapping the NLR)and likely isotropic

(Cameron et al. 1993, Bock et al. 1998, 2000, Tomono et al. 2001)

12.5 µm

Details not well fit by standard astronomical silicate

Sturm et al. 2005

peak shift:- temperature- grain sizes- crystallization- composition

used synthetic ISM-extinction curve from Weingartner and Draine (2001)

2e3 erg s-1cm-2

2e5 erg s-1cm-2

Fitting of NGC3998:

Rdust: ~200 L460.5pc

L46~ 4.84e-3

(estimated by scaling Lbol of PG0050+124 by ratio of x-ray (2-10keV) luminosities)

Rdust ~ 14 pc D ~ 30 pc

Using illuminated cloud models: Brent Groves (MPA)

Hotter component also needed

From Imaging : D ~ 35 pc

Jacquelin Kessler-Silacci et al.

wavelength [µm]

180 K

1100 K

ISM extinction curveby Weingartner and Draine (2001)

The QUEST-projectEvolution of Activity in Massive Gas-Rich Mergers

-study basic physical processesinvolved in

-creating massive early type hosts -growing/feeding of massive BH

in galaxy mergers

50% of cosmic star formation at high zand most of the big BH´s appear to beformed in this process

understand this process better in the local univers apply knowledgeto high z.

-Test the Sanders-scenario

…

M ~ 107 – 1010 M

~1pc

~100 pc – few kpc

Rout < 100 pc

Rout < 35 pc : NGC 1068 (Keck 8-25 µm Bock et al 00) NGC 4151 (Gemini 10 & 18 µm Radomski et al 03)

Follow-up SUBARU (COMICS) observation of NGC3998A preliminary result

I11.7

-I8.6

1.88 x

6.87.11

)(6.11

7.11

)(6.8

6.8

6.8

7.116.87.11 88.1 II

Fs

Fc

c

cIII

total

total

fluxd

en

sity

[Jy

]

S11.7

c11.7

C8.6

I

2MASS JHK-band (NED)

image size : 200 pc2

(together with DaigoTomono)

Similar Galactic SEDs:

flared, passive irradiated protostellar disks

Dullemond et al. 2001, 2004

… but of course cannot be scaled simply!