Mapping the circumnuclear dust in nearby AGN with MIDI Konrad R.W. Tristram, Klaus Meisenheimer Max-Planck-Institut für Astronomie Heidelberg, Germany Collaborators: Walter Jaffe, David Raban, Bill Cotton

Konrad R. TristramPage 2 Motivation Unified AGN model: Geometrical effects lead to different manifesta- tions (e.g. Seyfert 1 & 2) Our goal: Resolve the dust distri- bution directly for nearby AGN Broad Line Region Accretion Disk Obscuring Torus Ionisation Cone Black Hole

Konrad R. TristramPage 3 Circinus: the galaxy Spiral galaxy SA(s)b, i = ~65° RA = 14h 13m, DEC = −65° 20’ Seyfert type 2 4 × 10 6 M  nucleus Distance ~4 Mpc → 50 mas ~ 1 pc unresolved in MIR 2MASS J, H, K s colour mosaic

Konrad R. TristramPage 4 Circinus: MIDI observations The Circinus UV coverage: 21 fringe tracks, 16 photometries Period 72, (U3-U2) Period 73, (U3-U2) Period 74, (U3-U4) Period 75, (U2-U3) Period 77, (U2-U3) u in m v in m U2-U4

Konrad R. TristramPage 5 Circinus: total flux Wavelength in µm Flux in Jy Circinus, total flux from all observations

Konrad R. TristramPage 6 Circinus: correlated flux Wavelength in µm Flux in Jy PA= 44°, BL=49.4m PA= 54°, BL=51.1m PA= 57°, BL=51.7m PA= 88°, BL=58.2m PA=120°, BL=62.0m PA=131°, BL=62.4m Circinus, observed: N

Konrad R. TristramPage 7 Circinus: modeling Two blackbody Gaussians: DEC in mas RA in mas11 µm Log of model flux distribution at 11µm Size:σ 1 = 9 mas Ellipticity:ε 1 =0.61 Temperature:T 1 =400 K Filling factor:f 1 =1.0 Size:σ 2 =42 mas Ellipticity:ε 2 =0.03 Temperature:T 2 =300 K Filling factor:f 2 =0.5 Silicate depth:τ SiO =1.3 Position angle:α =60°

Konrad R. TristramPage 8 Circinus: environment Known geometry 1’’~ 20 pc O[III] Expected torus configuration Wilson et al. 2000

Konrad R. TristramPage 9 Circinus: model result RA in mas DEC in mas pc 0.4 pc Dust torus in Circinus supports unified scheme

Konrad R. TristramPage 10 Centaurus A (NGC 5128) Elliptical galaxy RA = 13h 25m DEC = −43° 01’ Radio jet 6 × 10 7 M  nucleus Distance 3.8 Mpc → 53 mas ~ 1 pc Merger

Konrad R. TristramPage 11 Centaurus A: results Flux in Jy PA~108°, BL~60.3m PA~ 37°, BL~45.3m Total Photometry Wavelength in µm N No dusty torus in Centaurus A

Konrad R. TristramPage 12 Conclusions Circinus: –small hot and large cold component –orientation perpendicular to ionisation cone Centaurus A –weak extended dust component –major emitter in MIR: synchrotron source Weaker targets: –hardly resolved Paranal, February 2005