Cosmic Equation of state from Strong Gravitational Lensing Systems
  Accelerating expansion of the Universe is a great challenge for both physics
and cosmology. In light of lacking the convincing theoretical explanation, an
effective description of this phenomenon in terms of cosmic equation of state
turns out useful.
  The strength of modern cosmology lies in consistency across independent,
often unrelated pieces of evidence. Therefore, every alternative method of
restricting cosmic equation of state is important. Strongly gravitationally
lensed quasar-galaxy systems create such new opportunity by combining stellar
kinematics (central velocity dispersion measurements) with lensing geometry
(Einstein radius determination form position of images).
  In this paper we apply such method to a combined data sets from SLACS and LSD
surveys of gravitational lenses. In result we obtain the cosmic equation of
state parameters, which generally agree with results already known in the
literature. This demonstrates that the method can be further used on larger
samples obtained in the future. Independently noticed systematic deviation
between fits done on standard candles and standard rulers is revealed in our
findings. We also identify an important selection effect crucial to our method
associated with geometric configuration of the lensing system along line of
sight, which may have consequences for sample construction from the future
lensing surveys.
