The nature and structure of obscuration...The nature and structure of obscuration Roberto Maiolino...
Transcript of The nature and structure of obscuration...The nature and structure of obscuration Roberto Maiolino...
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The nature and structureof obscuration
Roberto MaiolinoAstronomical Observatory of Rome
Guido RisalitiArcetri Astrophysical Observatory
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400 pc
2”=140pc
CO
[OIII]
Schinnerer+00Tacconi+
Obscuration on large scales (>100 pc)~
Malkan+97
Guainazzi+05 dust
Comptonthin Compton
thick
dust lanesmolecular rings/diskshost galaxy obsuration
Compton thinAV ~ a few mags
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Obscuration on small scales («100pc)
IRAM - 12CO(2-1)
2” = 140pc
Schinnerer+00
NGC1068
10pc
Davies+07
SINFONI - H2 (1-0)S1
1 pc3 pc
VLTI - MIR
VLBA - H2O maserVLBA - Continuum
Jaffe+04
Greenhill+97Gallimore+97
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X-ray absorption on small scales: NH variability
toru
s
BLR
Risaliti+ 02
Δt ~ years
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X-ray absorption on small scales: NH variability
toru
s
BLR
Risaliti+ 02
Δt ~ years
Risaliti+ 06Elvis+ 05Puccetti+ 06
Δt ~ weeks
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X-ray absorption on small scales: NH variability
toru
s
BLR
Risaliti+ 02
Δt ~ years
Risaliti+ 06Elvis+ 05Puccetti+ 06
Δt ~ weeks
toru
s
BLR
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Dust absorption on small scales:inner radius ~ sublimation radius > BLR
NIR NIROpt/UV
BroadLines
NIR (K-band)
Sy1’s near-IR reverberation Suganuma+06
Rin ∝ L0.5
0.01 - 0.3 pc
Δt
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Bulk of X-rayabsorption ~ BLR < dust sublimation radius
⇓- decoupling of dust and gas obscuration- AV/NH « Galactic
Nardini+07
Especially relevant at mid-IR wavelengths:AGNs are never totally absorbed at 5-20µm (A8µm< 3mag)⇒ mid-IR excellent window to detect AGNs
A8µm~0
A8µm~0.5
A8µm~2
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However X-ray and dusty absorbersgenerally know each other...
optical classification
Log NH (cm-2) NHX (cm-2)
9.7
µm
sili
cate
stre
ngth
Risaliti+99 Shi+06Hao+07
mid-IR absorption
⇒ generally ~ coplanar dustyabsorber
dustyabsorberX-ray
absorber
absorption
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Geometry and structure of the dusty absorber
Uniform dust distribution models
Broad IR SED-> wide range of Tdust
Large torus (~100 pc) required...Granato+97
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Geometry and structure of the dusty absorber
Uniform dust distribution models
Broad IR SED-> wide range of Tdust
Large torus (~100 pc) required...Granato+97
...but high-resolution 10-20µm data -> ~pc scale
Jaffe+04Ponchelet+06
Mason+06
T = 320 K
R ≤ 1.7 pc
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Clumpy models:wide Temperature range on small scales
λ (µm)
λ F λ
Nenkova+02,06Elitzur+06Hönig+06
Rin = RsublimationRout ≈ 5-30 Rin
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-200 0 200
-200
0
200
DE
C in
mas
RA in mas
Clumpy models: some warnings
VLTI - 11µmCIRCINUS nucleus
flux model distribution
size ~ 0.2 pcellipticity = 0.6T = 330 K
maserdisk
plane
ionization
coneTristram+07
N2H+(1-0)
M ~ 5 MMW molecular core
gas-dust properties ≠ diffuse ISM
Caselli+02
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Dust properties in AGNs
Extinction curves give different results
QSO1’sSMC-like ⇒ small grains
Reichards+03, Hopkins+04
strongly reddened AGNsflattened ⇒ large grainsGaskell+04,06Czerni+04(Willott+05)
No contradiction:they sample differentmedia
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Sani+07
Dust properties in AGNs
τcont
τ CO
,Hyd
roc.
Continuum anddusty featuresabsorptions do
not correlate
broad variety of dust properties
⇓
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Stability of thedusty absorber
Must cover a large solid angle (~60-80%)⇒ geometrically thick (as observed)
- Radiation pressure Krolik’07
- Warped disk (observed in maser emission) Nayakshin’05, Caproni+06
- Not static, but dynamical stability: outflowing clouds Elitzur+06, Elvis+02,03 Everett & Konigl 00
- Nuclear stellar winds Nayakshin+06
- Turbolence by SNe Wada+04, Watabe+05 evidence for recent
nuclear starburstDavies+06, Mueller-Sanchez+06SDSS results -> Heckman’s talk
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Evidence for alternative geometriesPowerful, obscured AGNs
without NLR(generally U/LIRGs)
Imanishi+07,04, Franceschini+03,Maiolino+03, Ballo+04, Caccianiga+07...
in some cases theNLR is obscured
by dust in the host galaxyHaas+06
talks by Martinez-Sansigre,Polletta, Alonso-Herrero
in some cases theNLR does not exist
Armus+07
6.2µm PAH EW (µm)
[NeV
]14.
3µm
/ [N
eII]1
2.8µ
m
4π nuclear obscuration?
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Covering factor versus luminosityContrasting results from X-ray and optical surveys
Ueda+ 04, Simpson+05, La Franca+05,Hasinger’06, Barger+05, Akylas+06,Steffen+04
AGN2 / AGN1 ratiodecreases with luminosity
Dwelly+06, Wang+07
Ascribe the effect to incompleteness and selection effectssee also Zakamska’s talk
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Covering factor versus luminosityAlternative approach: use only AGN1s
Maiolino+07
(but missing obscuration onhost galaxy scales)
IRbump
bluebump
νlo
g [ λ
Lλ(6
.7µ
m) /
λLλ
(510
0A) ]
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Covering factor versus luminosity
Alternative approach: use only AGN1s
Bianchi+07
Same result forthe X-ray Compton thick
absorber/reflector
Iwasawa-Taniguchi effect (Balwdin for FeK line)L(2-10 keV) [1044 erg s-1]
EW
(FeK
line
) [e
V]IR
bumpblue
bump X-raycont.
FeK
ν
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Physical origin of the Covering Factor (CF) dependence on luminosity
+ “Receding torus” (increasing Rsublimation) Lawrence’91 - does not match observed trends Simpson’05 - only for dusty torus
+ Gravitational effect of BH and galactic disk Lamastra+06 - CF should correlate with MBH
+ Radiation pressure - CF should correlate with L/LEdd
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Covering factor inconsistencybetween local and high-z Sy’s
AGN1
AGN2 thin
Gilli+ 07
Alonso-Herrero+06, Fiore+07,Daddi+07, Martinez-Sansigre+06,
Polletta+06, Tozzi+06
Resolved X-ray background (