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SMBH accreting stars in axisymmetric galactic nuclei Shiyan Zhong in collaboration with Peter Berczik and Rainer Spurzem
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Highlight Accretion rate (and its evolution) Shape of loss-cone in axisymmetric potential Origin of TD stars
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Models Rotating King Model, with W=6.0, ω=0.3, 0.6 For comparison also ω=0.0 G=M=1, E= -0.25 N=64, 128 K. Equal mass: m=1/N. BH mass 1% of the total mass. Free moving, tidal radius 10 -3, 10 -4
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Spherical symmetric case: Plummer vs non-rotating King model
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King model with different rotation:
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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.
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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.
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At the time of disruption, star must have J≤J lc
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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.
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effective area of loss-cone and compare to that in spherical system.
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E distribution of TD stars at their last apocenter
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J distribution of TD stars at their last apocenter
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Jz distribution of TD stars at their last apocenter
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Origin of TD stars Distribution of R max (last apocenter position)
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Origin of TD stars Distribution in θ dimension Blue curve is sin( θ ), when the last apocenters are uniformly distributed in θ
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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.
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Orbit in axisymmetric potential Inside BH's influence radius: SAT and saucer Outside BH's influence radius: basically chaotic
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R max distribution after orbit classification
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θ distribution after orbit classification
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Last apocenter position distribution in real space
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Thank you for your attention!
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