Speaker
Prof.
Alexander Zakharov
(leading researcher)
Description
Now there are two basic observational techniques to investigate a
gravitational potential at the Galactic Center, namely, a)
monitoring the orbits of bright stars near the Galactic Center to
reconstruct a gravitational potential; b) measuring a size and a
shape of shadows around black hole giving an alternative possibility
to evaluate black hole parameters in mm-band with VLBI-technique. At
the moment one can use a small relativistic correction approach for
stellar orbit analysis (however, in the future the approximation
will not be not precise enough due to enormous progress of
observational facilities) while now for smallest structure analysis
in VLBI observations one really needs a strong gravitational field
approximation. We discuss results of observations, their
conventional interpretations, tensions between observations and
models and possible hints for a new physics from the observational
data and tensions between observations and interpretations. We
discuss an opportunity to use a Schwarzschild metric for data
interpretation or we have to use more exotic models such as Reissner
-- Nordstrom or Schwarzschild -- de-Sitter metrics for better
fits. From an analysis of S2 star trajectory we obtained a graviton
mass constraint $m_{g} < 2.9 \times 10^{-21}$~eV which is comparable
and consistent with the constraint $1.2 \times 10^{-22}$~eV given
recently by the LIGO collaboration from an analysis of gravitational
wave signal corresponding to a binary black hole coalescence.
Primary author
Prof.
Alexander Zakharov
(leading researcher)
