SMBH accreting stars in axisymmetric galactic nuclei Shiyan Zhong in collaboration with Peter Berczik and Rainer Spurzem

Highlight Accretion rate (and its evolution) Shape of loss-cone in axisymmetric potential Origin of TD stars

Models Rotating King Model, with W=6.0, ω=0.3, 0.6 For comparison also ω=0.0 G=M=1, E= N=64, 128 K. Equal mass: m=1/N. BH mass 1% of the total mass. Free moving, tidal radius 10 -3, 10 -4

Spherical symmetric case: Plummer vs non-rotating King model

King model with different rotation:

Shape of Loss-cone In spherical symmetric case, J≤J lc, (Frank & Rees, 1976) In axisymmetric case, J z ≤J lc. Because J is not conserved, boundary in J dimension can be a few times larger than J lc. (Magorrian & Tremaine, 1999) Measured in (E,J,J z ) phase space by performing scattering experiment.

Hidden parameter - θ angle of apocenter - also matters To determine a test particle's orbit (apocenter position), one need to give its E, J, J z and θ Then we are dealing with a 4-dimension space which is hard to draw on a plane. Not all orbits starting from red zone can hit the BH.

At the time of disruption, star must have J≤J lc

loss-cone shape in different rotating model In ω=0.6 model, variation in J is larger and faster, so the outer boundary is larger than that in ω=0.3 model. Also the red region around small J disappeared. In all energy slice, ω=0.6 model always occupy larger area.

effective area of loss-cone and compare to that in spherical system.

E distribution of TD stars at their last apocenter

J distribution of TD stars at their last apocenter

Jz distribution of TD stars at their last apocenter

Origin of TD stars Distribution of R max (last apocenter position)

Origin of TD stars Distribution in θ dimension Blue curve is sin( θ ), when the last apocenters are uniformly distributed in θ

Comparison between 2 rotating models: In higher rotation model the double peak feature is more pronounced. Because the cluster is flatter, the distribution is more concentrated toward the equatorial plane.

Orbit in axisymmetric potential Inside BH's influence radius: SAT and saucer Outside BH's influence radius: basically chaotic

R max distribution after orbit classification

θ distribution after orbit classification

Last apocenter position distribution in real space

Thank you for your attention!