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Title: Observing the shadow of Einstein-Maxwell-Dilaton-Axion black hole

Journal Article · · Journal of Cosmology and Astroparticle Physics
;  [1]
  1. Institution, Theoretical Physics, Lanzhou University, Lanzhou, 730000 (China)

In this paper, the shadows cast by Einstein-Maxwell-Dilaton-Axion black hole and naked singularity are studied. The shadow of a rotating black hole is found to be a dark zone covered by a deformed circle. For a fixed value of the spin a, the size of the shadow decreases with the dilaton parameter b. The distortion of the shadow monotonically increases with b and takes its maximal when the black hole approaches to the extremal case. Due to the optical properties, the area of the black hole shadow is supposed to equal to the high-energy absorption cross section. Based on this assumption, the energy emission rate is investigated. For a naked singularity, the shadow has a dark arc and a dark spot or straight, and the corresponding observables are obtained. These results show that there is a significant effect of the spin a and dilaton parameter b on these shadows. Moreover, we examine the observables of the shadow cast by the supermassive black hole at the center of the Milky Way, which is very useful for us to probe the nature of the black hole through the astronomical observations in the near future.

OSTI ID:
22369888
Journal Information:
Journal of Cosmology and Astroparticle Physics, Vol. 2013, Issue 11; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 1475-7516
Country of Publication:
United States
Language:
English

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