The Orientation of the AGNs

1. The Orientation of the AGNs 沈世银 上海天文台 合作者：邵正义，顾敏峰

2. outline • Introduction:orientation as a key parameter of AGN schema • Observation:type 2 AGN host spirals are biased to these with low inclinations • Model:this orientation bias can be explained with an intrinsic correlation between the accretion disk and stellar disk

3. AGN unification Orientation: the key parameter of the AGN schema

4. Direct Mapping of the AGN orientation • Radio Jet • obscuring torus • HST • VLT MIDI NGC 4261 NGC1068

5. Indirect diagnostic • Core and lobe emission ratio R of radio-loud QSOs • Core emission is Doppler boosted when observed down the axis • Radio spectral index • Core emission is flatter (Wilman et al. 2008) • Broad line width • Anti-correlation between R and FWHM of H • Structure of broad line region • V=f*FWHM, MBH=fRBLR FWHM2/G • Disk like geometry (Decarli et al. 2008) • Structure of narrow line region • Low O[III]/[OIV] and O[III] 4363/ 5007 ratios in Seyfert 1s • Implication on nuclear obscurers

6. Spatial correlation between the AGN and host galaxies • jet VS stellar disk (Kpc VS Kpc) • wide distribution, jet avoid lying close to the plane of the dust disks (Schimitt et al. 2002, 20 radio galaxies) • Kpc scale radio jet orient randomly with respect to the host galaxy axes. (Gallimore et al. 2006, 19 objects) • Type 1 AGNs are known to be biased against edge-on galaxies • Optically selected (keel 1980) • Soft X-ray Seyferts ( Simoce et al. 1997) • Hard X-ray sample do not show such a bias (Elvis 1982) • Conclusion • Extra stellar dust obscuration? • Intrinsic correlation between the angular momentum of the accretion disk and stellar disk? • Small number statistics, selection effect. • Excess of face-on spirals hosting both type 1 and 2 AGNs for a spectroscopic selected sample (McLeod & Rieke 1995)

7. Correlation between the orientation of stellar disk and accretion disk? Orientation of the stellar disks hosting type 2 AGNs

8. Why type 2 AGNs hosted by spirals? • SDSS • large and homogenous sample of galaxies and AGNs • Type 2 AGNs • Global properties of the hosts are not contaminated by the nuclei • Well-defined control sample • Spiral galaxies • the inclination of the stellar disks can be well-defined by the shape parameter • Claudia de P. 2010, type 1 and 2 AGNs, hosts: spirals and ellipticals

9. Type 2 AGNs in SDSS DR7 • BPT diagram • Star forming VS AGN • Kewley et al. 2001 • Theoretical upper limit of starbursts • Kauffmann et al. 2003 • Empirical separation NAGN=109,832

10. AGNs hosted by spirals • fracDev<0.5: select spiral galaxies • Fcomp = fracDeV FdeV + (1 - fracDeV) Fexp • ~40% of galaxies are spiral • AGNs hosted by spirals • ~30% of AGNs hosted by spirals • b/a of late type galaxies • approximate the inclination of disk Disk height Disk ellipticity NAGN,spiral=32,618

11. ~32,600 type 2 AGNs hosted by spiral galaxies spatial correlation betweenaccretion disk and stellar disk distinctive physical properties of AGN host b/a distribution A control sample with the same physical properties as AGN hosts

12. Control sample of galaxies • The same distributions of • Stellar mass • Redshift • Concentration • D4000 • R50 • FracDev How about b/a? If there is no correlation between the orientations of the accretion disk and stellar disk, the control sample will have the same b/a distribution as the AGN sample.

13. The type 2 AGN hosts are biased to low inclination disks:The orientation of the accretion disk and stellar disk is correlated. How to quantify this result?

14. Incl= f(b/a| ,,,) (, ) stellar disk structure parameter = C/A :disk height = (1-B/A) : disk ellipticity AGN hosts have the same (, ) distribution as control galaxies! (, ) viewing angle : inclination  : position angle Control galaxies: random AGN hosts: preferred angle? the shape of spiral galaxies

15. ,  distributions Non-negative least square linear regression

16. viewing angle of AGN hosts • Viewing angle of stellar disk (S, S) • Viewing angle of the accretion disk (A, A) • Tilt angle between accretion disk and Tilt stellar disk AS • Opening angle of torus T • Type II AGN: 90-A< T s AS A 2T

17. Toy model (, ) distribution Random viewing angle of stellar disk (S, S) b/a of galaxy Viewing angle of accretion disk (A0, A0) Tilt angle AS NAGN/NAGN(b/a) 90-A0 < T Type II AGN fraction f2 (, ) distribution Viewing angle of observed AGN (A, A) b/a of AGN host

18. Model results • IfAS random or T=90 • cosAS: uniform distribution • NAGN/NGAL=1 • Non-random Assumption • cosAS follows Gaussian distribution, with most probable value AS =0, scatter As,m • AS,m=37 deg • T: free parameter • T =58 deg • f2=80%: in excellent agreement with the results in literature!

19. Discussion: luminosity dependence of T • f2: function of L[OIII] • T is smaller for higher luminosity AGNs Our AGNs 1 L¯=3.2x1026 W

20. Discussion:obscuration by stellar disks • Geometrically thick layer of obscuring material in the host galaxy plane (e.g. Elvis 1982)? • Disk obscuration model • Tours alignment independent of the stellar disk • Obscuration of stellar disk: tan () < C/A • Excess of AGNs with low b/a, no systematical trend • No free parameter!

21. Summary (Shen, Shao & Gu, ApJL 2010) • Orientation is the key parameter of the AGN schema • We select a sample of 32,618 type 2 AGNs hosted by spiral galaxies from SDSS DR7. • We build a control sample of galaxies, which are expected to have the same physical properties as the AGN hosts. • By comparing with the control galaxies, we find the AGN hosts are more likely to be viewed as edge-on. • The bias in the axis ratio (inclination) of the AGN hosts can be explained with a simple model that • the opening angle of the torus is ~60 degree • the mean tilt angle between the accretion disk and stellar disk is ~30 degree

22. Thanks