WMAP constraints on the generalized Chaplygin gas model

The generalized Chaplygin gas (GCG) model explains the recent accelerated expansion of the Universe via an exotic background fluid whose equation of state is given by p=−A/ρα, where A is a positive constant and 0<α⩽1. The model is an interesting alternative to scenarios involving scalar field potentials, with the ensuing unnatural fine tuning conditions for the underlying particle physics theories. We derive constraints on the parameter space of the model from bounds on the location of the first few peaks and troughs of the cosmic microwave background radiation (CMBR) power spectrum arising from recent WMAP and BOOMERanG data.