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The orbiting spot model gives constraints on the parameters of the supermassive black hole in the Galactic Center

Published online by Cambridge University Press:  01 August 2006

Leonhard Meyer
Affiliation:
I. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, 50937 Köln, Germany email: leo@ph1.uni-koeln.de
Andreas Eckart
Affiliation:
I. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, 50937 Köln, Germany email: leo@ph1.uni-koeln.de
Rainer Schödel
Affiliation:
I. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, 50937 Köln, Germany email: leo@ph1.uni-koeln.de
Michal Dovčiak
Affiliation:
Astronomical Institute, Academy of Sciences, Boční II, CZ-14131 Prague, Czech Republic
Vladimír Karas
Affiliation:
Astronomical Institute, Academy of Sciences, Boční II, CZ-14131 Prague, Czech Republic
Wolfgang J. Duschl
Affiliation:
Institut für Theoretische Physik und Astrophysik, Universität zu Kiel, 24098 Kiel, Germany Steward Observatory, The University of Arizona, 933 N. Cherry Ave. Tucson, AZ 85721, USA
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Abstract

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We report on recent polarimetric observations of the 18± 3 min quasi-periodicity present in near-infrared flares from Sagittarius A*. Observations in the K-band allow us a detailed investigation of the flares and their interpretation within the hot spot model. The interplay of relativistic effects plays a major role. By simultaneous fitting of the lightcurve fluctuations and the time-variable polarization angle, we give constraints to the parameters of the hot spot model, in particular, the dimensionless spin parameter of the black hole and its inclination. We consider all general relativistic effects that influence the polarization lightcurves. The synchrotron mechanism is most likely responsible for the intrinsic polarization. We consider two different magnetic field configurations as approximations to the complex structure of the magnetic field in the accretion flow. Considering the quality of the fit, we suggest that the spot model is a good description of the origin for the QPOs in NIR flares.

Type
Contributed Papers
Copyright
Copyright © International Astronomical Union 2007

References

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