Dec 13 – 18, 2015
International Conference Centre Geneva
Europe/Zurich timezone

Measuring the Innermost Stable Circular Orbits of Supermassive Black Holes

Dec 16, 2015, 3:12 PM
Level -1, Room 17 (International Conference Centre Geneva)

Level -1, Room 17

International Conference Centre Geneva


Dr George Chartas (College of Charleston)


We present a promising new technique (g-distribution method) for measuring the innermost stable circular orbit (ISCO), the inclination angle (i), and the spin of a supermassive black hole. The g-distribution method involves measurements of the distribution of the energy shifts of the relativistic iron line emitted from the accretion disk of a supermassive black hole that is microlensed by stars in a foreground galaxy and a comparison of the measured g-distribution with microlensing caustic simulations. The method has been applied to the gravitationally lensed quasar RX J1131−1231 and initial results indicate that r_ISCO < 9 gravitational radii and i < 60 degrees. Further monitoring of RX J1131−1231 and other lensed quasars will provide tighter constraints on the inclination angles, ISCO radii and spins of the black holes of distant quasars.

Primary author

Dr George Chartas (College of Charleston)


Mr Carter Rhea (College of Charleston)

Presentation materials