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The The Large Scale StructureLarge Scale Structure of of Seyferts and LINERsSeyferts and LINERs
and and Implications for their Implications for their Central Central
EnginesEngines
Anca Constantin
Drexel University
AGN are not unbiased tracers of the whole galaxy population, with respect to mass:
- Seyferts are less clustered than galaxies less massive but actively accreting BHs
- LINERs cluster like galaxies. more massive but weakly active BHs
--with thanks to Michael Vogeley
The SDSS main galaxy sample -DR2
• 2627 sq. deg. footprint area • ~250,000 galaxies with spectra • 0 < z <~ 0.3• rdered < 17.77
• Broad-line objects (spectroscopically flagged as QSOs) excluded
The SDSS main galaxy sample -DR2
• 2627 sq. deg. footprint area • ~250,000 galaxies with spectra • 0 < z <~ 0.3• rdered < 17.77
• Broad-line objects (spectroscopically flagged as QSOs) excluded
“ Best” absolute magnitude limited sample
Finding AGN among SDSS galaxies
Seyferts
H II
nuclei
LINERs
Transition objects
emission-line
20% of all galaxies are strong line-emitters
among which: 52% H II20% (pure) LINERs7% Transition Objects
5% Seyferts
The Clustering Amplitude r0:
H IIs: r0= 5.7 0.2 less clustered than galaxies
Seyferts: r0= 6.0 0.6
less clustered than galaxies
LINERs: r0= 7.3 0.6 clustered like galaxies
r0 is measured in h-1 Mpc = scale where the probability of finding a galaxy pair is 2 random
all galaxies: r0= 7.8
0.5 Absolute Magnitude limited samples,
-21.6 <M < -20.2
The Clustering Amplitude r0:
H IIs: r0= 5.7 0.2 less clustered than galaxies
Seyferts: r0= 6.0 0.6
less clustered than galaxies
LINERs: r0= 7.3 0.6 clustered like galaxies
r0 is measured in h-1 Mpc = scale where the probability of finding a galaxy pair is 2 random
all galaxies: r0= 7.8
0.5
higher peaks in the density field are more clustered
Seyferts & H II’s: - less massive Dark Matter halos
LINERs: - more massive Dark Matter halos
Absolute Magnitude limited samples, -21.6 <M < -20.2
The Clustering Amplitude r0:
H IIs: r0= 5.7 0.2 less clustered than galaxies
Seyferts: r0= 6.0 0.6
less clustered than galaxies
LINERs: r0= 7.3 0.6 clustered like galaxies
r0 is measured in h-1 Mpc = scale where the probability of finding a galaxy pair is 2 random
all galaxies: r0= 7.8
0.5
higher peaks in the density field are more clustered
Seyferts & H II’s: - less massive Dark Matter halos
LINERs: - more massive Dark Matter halos
Absolute Magnitude limited samples, -21.6 <M < -20.2
MBH Seyferts < MBHLINERs
MDM halo ~ MBH
(Ferraresse 2002, Baes et al. 2003)
Driven by the host morphology?
H IIs Seyferts LINERsblue red-ish red-ish, KScolor = 0.617
late type earlier types like Seyferts! KSconc = 0.104
blue red
earlylate
Driven by the host morphology? NO!
H IIs Seyferts LINERsblue red-ish red-ish, KScolor = 0.617
late type earlier types like Seyferts! KSconc = 0.104
blue red
earlylate
Low L[O I]: r0= 13.15
1.09LINER dominated
High L[O I]: r0= 6.1 0.3
H II dominated
Low L[O III]: r0= 8.8 0.7
LINER dominated
High L[O III]: r0= 6.2 0.6
almost no LINERs!mostly H II
high L[O I]
high L[O III]
low L[O I]
low L[O III]
lowest L[O I],[O III] objects = strongly clusteredhighest L[O I],[O III] objects = weakly clustered
Different availability of fuel?
LINERs show particularly low levels of obscuration
& gas densities
Seyferts exhibit generally
high gas densities& moderately high NHI
Summary & Possible interpretation
H IIs Seyferts LINERs
hosts: blue red-ish red-ish, late type earlier types like the Seyferts
r0: weakly weakly clustered like
clustered clustered average galaxies
fueling average relatively high (very) low rate: -efficient? -inefficient?
gas low high lower thandensity: in Seyferts
obscuration: high wide range (very) lowBH mass: small small large
life-time: ? short long
Constantin & Vogeley 2006, in ApJ today
Stellar massBH mass
Accretion rate, [O I] Accretion rate, [O III]
Stellar ages Obscuration
Dist to 3rd nearest Dist to 1st nearest