Spherically symmetric dark energy structures are investigated in the framework of a generalized Chaplygin gas (GCG), which has an equation of state of the form $P = - A/\rho^{\alpha}} $. We also study these in a modified GCG equation of state, which includes a matter term, i.e. $P = \sigma^{2} \rho - A/\rho^{\alpha}$. The results of the latter are then compared with some observational data on low-surface-brightness galaxies which are supposed to be dominated by dark matter.
