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Title: Measuring the Innermost Stable Circular Orbits of Supermassive Black Holes

Abstract

We present a promising new technique, the g -distribution method, for measuring the inclination angle ( i ), the innermost stable circular orbit (ISCO), and the spin of a supermassive black hole. The g -distribution method uses measurements of the energy shifts in the relativistic iron line emitted by the accretion disk of a supermassive black hole due to microlensing by stars in a foreground galaxy relative to the g -distribution shifts predicted from microlensing caustic calculations. We apply the method to the gravitationally lensed quasars RX J1131–1231 ( z {sub s} = 0.658, z {sub l} = 0.295), QJ 0158–4325 ( z {sub s} = 1.294, z {sub l} = 0.317), and SDSS 1004+4112 ( z {sub s} = 1.734, z {sub l} = 0.68). For RX J1131−1231, our initial results indicate that r {sub ISCO} ≲ 8.5 gravitational radii ( r {sub g}) and i ≳ 55° (99% confidence level). We detect two shifted Fe lines in several observations, as predicted in our numerical simulations of caustic crossings. The current Δ E distribution of RX J1131–1231 is sparsely sampled, but further X-ray monitoring of RX J1131–1231 and other lensed quasars will provide improved constraints on the inclination angles,more » ISCO radii, and spins of the black holes of distant quasars.« less

Authors:
;  [1];  [2];  [3];  [4]; ;  [5]
  1. Department of Physics and Astronomy, College of Charleston, Charleston, SC 29424 (United States)
  2. Physics Department and McDonnell Center for the Space Sciences, Washington University in St. Louis, 1 Brookings Drive, CB 1105, St. Louis, MO 63130 (United States)
  3. Department of Astronomy, The Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States)
  4. Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, Norman, OK 73019 (United States)
  5. Physics Department, United States Naval Academy, Annapolis, MD 21403 (United States)
Publication Date:
OSTI Identifier:
22661337
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 837; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCRETION DISKS; BLACK HOLES; COMPUTERIZED SIMULATION; DISTRIBUTION; EMISSION; GALAXIES; GRAVITATIONAL LENSES; INCLINATION; IRON; LIMITING VALUES; ORBITS; QUASARS; RELATIVISTIC RANGE; SPIN; STARS; SUPERMASSIVE STARS; X RADIATION

Citation Formats

Chartas, G., Zalesky, L., Krawczynski, H., Kochanek, C. S., Dai, X., Morgan, C. W., and Mosquera, A., E-mail: chartasg@cofc.edu. Measuring the Innermost Stable Circular Orbits of Supermassive Black Holes. United States: N. p., 2017. Web. doi:10.3847/1538-4357/AA5D50.
Chartas, G., Zalesky, L., Krawczynski, H., Kochanek, C. S., Dai, X., Morgan, C. W., & Mosquera, A., E-mail: chartasg@cofc.edu. Measuring the Innermost Stable Circular Orbits of Supermassive Black Holes. United States. doi:10.3847/1538-4357/AA5D50.
Chartas, G., Zalesky, L., Krawczynski, H., Kochanek, C. S., Dai, X., Morgan, C. W., and Mosquera, A., E-mail: chartasg@cofc.edu. Wed . "Measuring the Innermost Stable Circular Orbits of Supermassive Black Holes". United States. doi:10.3847/1538-4357/AA5D50.
@article{osti_22661337,
title = {Measuring the Innermost Stable Circular Orbits of Supermassive Black Holes},
author = {Chartas, G. and Zalesky, L. and Krawczynski, H. and Kochanek, C. S. and Dai, X. and Morgan, C. W. and Mosquera, A., E-mail: chartasg@cofc.edu},
abstractNote = {We present a promising new technique, the g -distribution method, for measuring the inclination angle ( i ), the innermost stable circular orbit (ISCO), and the spin of a supermassive black hole. The g -distribution method uses measurements of the energy shifts in the relativistic iron line emitted by the accretion disk of a supermassive black hole due to microlensing by stars in a foreground galaxy relative to the g -distribution shifts predicted from microlensing caustic calculations. We apply the method to the gravitationally lensed quasars RX J1131–1231 ( z {sub s} = 0.658, z {sub l} = 0.295), QJ 0158–4325 ( z {sub s} = 1.294, z {sub l} = 0.317), and SDSS 1004+4112 ( z {sub s} = 1.734, z {sub l} = 0.68). For RX J1131−1231, our initial results indicate that r {sub ISCO} ≲ 8.5 gravitational radii ( r {sub g}) and i ≳ 55° (99% confidence level). We detect two shifted Fe lines in several observations, as predicted in our numerical simulations of caustic crossings. The current Δ E distribution of RX J1131–1231 is sparsely sampled, but further X-ray monitoring of RX J1131–1231 and other lensed quasars will provide improved constraints on the inclination angles, ISCO radii, and spins of the black holes of distant quasars.},
doi = {10.3847/1538-4357/AA5D50},
journal = {Astrophysical Journal},
issn = {0004-637X},
number = 1,
volume = 837,
place = {United States},
year = {2017},
month = {3}
}