A number of X-ray space missions like, ASCA, XMM-Newton, Chandra got a lot of information about Fe Kα lines and other X-ray lines. Recent X-ray observations of microquasars and Seyfert galaxies reveal broad emission lines. Simulations indicate that at low inclination angles the lines have characteristic two-peak profiles. However, at high inclination angles two additional peaks arise. This phenomenon was discovered by Matt et al. (1993) for the Schwarzschild black hole metric case. We check and confirm their hypothesis about such a structure of the spectral line shape for the Kerr metric case. We use no astrophysical assumptions about the physical structure of the emission region except the assumption that the region should be narrow enough. Positions and heights of these extra peaks drastically depend on both the radial coordinate of the emitting region (annuli) and the inclination angle. It was found that these extra peaks arise due to gravitational lens effect in the strong gravitational field, namely they are formed by photons with some number of revolutions around black hole. This conclusion is based only on relativistic calculations without any assumption about physical parameters of the accretion discs. We discuss how analysis of the iron spectral line shapes could give information about an upper limit of magnetic field near black hole horizon. Based on results of numerical simulations we discussed origins of double peaked and double horned profiles in the framework of narrow emission ring model. In 2007 Radioastron telescope will be launched and it will be a generalization of VLBI technique using 10-m radio telescope in space. We have proposed a procedure to measure parameters of the black hole in the Galactic Center. We discuss shapes of glories (mirages) formed near rapidly rotating Kerr black hole horizons and propose a procedure to measure masses, changes and spins analyzing these forms of mirages. That is GR effect in the strong gravitational field near black hole horizon. We also propose a procedure to measure shapes of mirages (shadows) and to evaluate the black hole spin as a function of the position angle of a distant observer.

Measuring the Supermassive Black Hole Parameters with Space Missions

DE PAOLIS, Francesco;NUCITA, Achille;INGROSSO, Gabriele
2007-01-01

Abstract

A number of X-ray space missions like, ASCA, XMM-Newton, Chandra got a lot of information about Fe Kα lines and other X-ray lines. Recent X-ray observations of microquasars and Seyfert galaxies reveal broad emission lines. Simulations indicate that at low inclination angles the lines have characteristic two-peak profiles. However, at high inclination angles two additional peaks arise. This phenomenon was discovered by Matt et al. (1993) for the Schwarzschild black hole metric case. We check and confirm their hypothesis about such a structure of the spectral line shape for the Kerr metric case. We use no astrophysical assumptions about the physical structure of the emission region except the assumption that the region should be narrow enough. Positions and heights of these extra peaks drastically depend on both the radial coordinate of the emitting region (annuli) and the inclination angle. It was found that these extra peaks arise due to gravitational lens effect in the strong gravitational field, namely they are formed by photons with some number of revolutions around black hole. This conclusion is based only on relativistic calculations without any assumption about physical parameters of the accretion discs. We discuss how analysis of the iron spectral line shapes could give information about an upper limit of magnetic field near black hole horizon. Based on results of numerical simulations we discussed origins of double peaked and double horned profiles in the framework of narrow emission ring model. In 2007 Radioastron telescope will be launched and it will be a generalization of VLBI technique using 10-m radio telescope in space. We have proposed a procedure to measure parameters of the black hole in the Galactic Center. We discuss shapes of glories (mirages) formed near rapidly rotating Kerr black hole horizons and propose a procedure to measure masses, changes and spins analyzing these forms of mirages. That is GR effect in the strong gravitational field near black hole horizon. We also propose a procedure to measure shapes of mirages (shadows) and to evaluate the black hole spin as a function of the position angle of a distant observer.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11587/114658
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