1. AGN10-dall’orizzonte degli eventi all’orizzonte cosmologico Roma 11/09/2012 Eleonora Sani Co-Is: Davies, Sternberg, Gracia-Carpio, Hicks, Tacconi, Genzel, Engel, Vollmer, Schinnerer, Garcia-Burrillo Usero, Orban de Xivry Phisical properties of dense molecular gas in centres of Seyfert galaxies

2. Introduction Torus structure AGN-SF connection Stellar and molecular gas kinematics Motivation: Trace the dense molecular gas The origin of huge velocity dispersion Results : - - PdBI data cubes and observables - - DYSMAL - - Can the torus form stars? Outline E. Sani AGN10 Roma 11/09/2012

3. Torus Properties molecular gas and dust optically thick: it obscures the AGN if viewed edge on compact: tens of parsecs of radial extension vertically extended: several parsecs (provide collimation for ionized gas) Antonucci & Miller 1985 E. Sani AGN10 Roma 11/09/2012

4. Torus structure Nenkova+02, +08; Honig+06; Schartmann+08 Stellar radiation pressure (Thompson+05; Ballantyne 2008) Supernovae explosions (Wada & Norman 2002) Stellar winds (Nayakshin & Cuadra 2007) External gas accretion (Vollmer+08) Nuclear star formation can play an important role E. Sani AGN10 Roma 11/09/2012 Pier & Krolik 1992; Granato & Danese 1994 Efstathiou & Rowan-Robinson 1995; Shartmann+05; Fritz+06 Dust distribution: Smooth (continuous) Clumpy (discrete)

5. AGN-SF connection SF happens in all types of AGN (Schweitzer+06, Veilleux+09) even in the nuclear region (R < 200 pc) (Cid Fernandes +04) Sani+10 SF enhanced for M BH < 10 7 M  L/L edd > 0.5 BH growth and SF happens simultaneously E. Sani AGN10 Roma 11/09/2012

6. AGN-SF with high spatial resolution Davies+07 Recent (~40 Myr ago) but no longer starburst in the inner 100 pc (with spatial resolution ~10 pc) H 2 flux velocity v. dispersion Hicks+09 H2 1-0(S1) traces warm molecular gas at centres v/ σ < 1 with σ gas ~50-100 km/s distribution must be vertically extended with gas & stars spatially mixed random bulk motions must account for σ gas in AGN E. Sani AGN10 Roma 11/09/2012

7. Molecular gas tracers 1-0S(1) H 2 traces hot component of the gas (~1000 K) at the edges of clouds 1-0S(1) H 2 accounts for 10 -6 -10 -5 of the total gas mass it is not straightforward to derive the vertical extent of the torus and the origin of the huge σ gas Sani+12 HCN(1-0), HCO + (1-0) probe cold (~10- 100 K) and dense (n >3x10 4 cm -3 ) molecular gas (i.e. ~100-500 times the density traced by CO rotational transitions) Close to the AGN HCN, HCO + are stronger than CO Chemistry modified by the AGN radion has little impact on the gas kinematcs <1” resolution with PdBI E. Sani AGN10 Roma 11/09/2012

8. Kinematics of the dense gas ~1” resolution from PdBI – NGC 3227, 2273, 4051, 6951 (now also NGC 3079, 5033, 6764) Directly observable constraints: major & minor axis size Integrated line width FWHM~70-210 km/s Separation + PA of the red/blue channels Sani+12

9. Modelling the kinematics Use DYSMAL (Cresci +09, Davies +11) -Gaussian distribution for the luminosity and mass profiles -Fixed parameters: ϑ and PA --Elliptical beam (beam smearing is a key aspect of dynamical modeling) --Free parameters: R, H, M R -Thin disk --Line width is only ~2/3 of that observed -Thick disk --Can reproduce all observed characteristics --Intrinsic dispersion is 25-50 km/s for HCN and HCO+ - (about ~50% of H 2 1-0S(1) reported by Hicks+09) --Dispersion is due to a combination of beam smearing of velocity - gradients as well as V/ σ ~R/H~3-4 Q = √3 H 1 R (1+3*H 2 /R 2 ) f gas -Toomre Q parameter: -Q/Q c >1 always, i.e. dense gas is turbulent with NO ongoing SF

10. SF within the Torus? SF within 450 pc 305 pc 180 pc 370 pc NGC 3227: nuclear (<30 pc) SF is no more occurring (Davies +06) NGC 2273, NGC 3227, NGC 6951 show a circumnuclear stellar ring (Martini +03, Davies +06, Krips +07) with a decreasing stellar dispersion comp. to the nucleus (Barbosa +06) NGC 4051: PAH 3.3 not detected within the central 50 pc ( Rodrguez-Ardila & Viegas 2003) NGC 6951 PdBI NGC 2273 K-band LBT Pisces+Flao SF located in a circumnuclear ring

11. The model: starburst & torus evolution Vollmer, Beckert, & Davies 08 Phase I: short, massive gas infall generates a massive turbulent disk (Q~Qc) where SF occurs. Phase III: the mass acc. rate decrease significantly. The collisional disk become thin and transparent. Phase II: SN explosions clear the intracloud medium leaving a massive, geometrically thick collisional disk of dense gas clouds Thick disk Q > Q c

12. Conclusion & Future Work  We observed 4 Seyfert galaxies with the PdBI tracing HCN and HCO + molecular lines. The line emission is (marginally) resolved.  We measured morphological (dimension & position angle) and kinematical (channel separation & integrated line width) parameters. The most remarkable feature is the line width FWHM ~ 70-210 km/s  Observed parameters are well reproduced by a thick (R/H = V/ σ ) taking into account the beam smearing.  Increase the statistics: now available data for 3 more sources.  Add other AGN types to trace the torus structure in different environments and its evolution.  Use tracers at 1.3mm, e.g. HCN(3-2), to constrain the chemistry

13. Dynamical modelling of the data with DYSMAL Disk in vertical hydrostatic equilibrium: R/H = V/σ inclined disk with a Gaussian mass distribution elliptical beam shape (crucial for modelling marginally resolved sources to account for beam smearing) Free parameters are: R, H and a Mass scaling -Thin disk: linewidth and/or channel separation are NOT reproduced Thick rapidly rotating disk Source 2R(“) 2H(“) V rot (km/s) σ int (km/s) σ H2 (km/s) NGC2273 1.38 0.43 83.1 44.8 NGC3227 0.54 0.14 104 60.4 95.0 NGC4051 0.86 0.18 54.4 24.7 55.0 Dense gas has a THICK distribution

14. The Toomre Q parameter Q = κσ/(πGΣ), κ = √3 x Ω (uniform disk) Ω = V/R σ = V x R/H (thick disk) Σ = M/(πR 2 ) M d = (V 2 +3σ 2 )R/G Qc=0.68 (thick Isothermal disk) Dekel +09 Q = √3 H 1 R (1+3xH 2 /R 2 ) f gas