Open AccessSupermassive black hole at the galactic center
Author(s) -
A. F. Zakharov
Publication year - 2014
Publication title -
facta universitatis. series: physics, chemistry and technology
Language(s) - English
Resource type - Journals
eISSN - 2406-0879
pISSN - 0354-4656
DOI - 10.2298/fupct1402201z
Subject(s) - physics , galactic center , supermassive black hole , black hole (networking) , schwarzschild radius , sagittarius a* , intermediate mass black hole , charge (physics) , astrophysics , charged black hole , stellar black hole , center (category theory) , extremal black hole , galaxy , quantum mechanics , computer network , routing protocol , chemistry , routing (electronic design automation) , accretion (finance) , computer science , crystallography , link state routing protocol
We derive an analytical expression of a shadow size as a function of a charge in the Reissner - Nordstr?m (RN) metric. Using the derived expression we consider shadows for negative tidal charges and charges corresponding to naked singularities q=Q2/M2>1, where Q and M are black hole charge and mass, respectively. An introduction of a negative tidal charge q can describes black hole solutions in theories with extra dimensions, so following the approach we consider an opportunity to extend RN metric to negative Q2, while for the standard RN metric Q2 is always non-negative. We found that for q > 9=8 black hole shadows disappear. Significant tidal charges q=-6.4 are not consistent with observations of a minimal spot size at the Galactic Center observed in mm-band, moreover, these observations demonstrate that in comparison with the Schwarzschild black hole a Reissner-Nordstr?m black hole with a significant charge q ? 1 provides a better fit of recent observational data for the black hole at the Galactic Center.