Cosmic structure sizes in generic dark energy models
  The maximum allowable size of a spherical cosmic structure as a function of
its mass is determined by the maximum turn around radius $R_{\rm TA,max}$, the
distance from its centre where the attraction on a radial test particle due to
the spherical mass is balanced with the repulsion due to the ambient dark
energy. In this work, we extend the existing results in several directions. (a)
We first show that for $w\neq -1$, the expression for $R_{\rm TA, max}$ found
earlier using the cosmological perturbation theory, can be derived using a
static geometry as well. (b) In the generic dark energy model with arbitrary
time dependent state parameter $w(t)$, taking into account the effect of
inhomogeneities upon the dark energy as well, where it is shown that the data
constrain $w(t={\rm today})>-2.3$, and (c) in the quintessence and the
generalized Chaplygin gas models, both of which are shown to predict structure
sizes consistent with observations.
