1. BLACK HOLE at the GALACTIC CENTER
Paul T.P. Ho
Academia Sinica IAA
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2. Center of the Galaxy
Sgr A*
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3. WHY the GALACTIC CENTER?
Nearest Supermassive Black Hole
Inflow and Accretion Rate
Connection to the Galactic Disk
Best Resolution and Sensitivity
Paradigm for AGN’s
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4. Orbital Motions Around SgrA. Schödel et al. Nature 419,694 (10. 17
VLT 8-m UT4: NAOS/CONICA
Diffraction Limited : 2.18m
AOS closed on supergiant IRS7
(6" N): Strehl ratio over 40%
Seeing Halos removed by Wiener Filter
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5. 2.18m Images of Galactic Center
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6. Galactic Center Proper Motions
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7. Orbit of S2 Around SgrA*
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8. Orbit of S2 Around SgrA* Semimajor Axis: 0.119" = 5.5 lightdays
Orbital Period: years
Pericentre Distance: 15mas = 17 lighthours = 124 AU = 2100 Rsch = 70 Rtidal
Binding Mass: x Mo
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9. Recap the Proper Motions
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10. How Much Better ? Increased Resolution and Sensitivity.
Detect and Track Fainter Stars.
Detect even Faster Motions?
Better Constraints on Orbits, Accelerations.
Detect Tidal Distortions?
Detect Relativistic Motions at 100 Rsch ?
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