Probing dark energy inhomogeneities with supernovae

We discuss the possibility of identifying anisotropic and/or inhomogeneous cosmological models using type Ia supernova data. A search for correlations in current type Ia peak magnitudes over a large range of angular scales yields a null result. However, the same analysis limited to supernovae at low redshift shows a feeble anticorrelation at the 2 sigma level at angular scales theta approximate to 40 degrees. Upcoming data from, e. g., the SNLS ( Supernova Legacy Survey) and the SDSS-II ( SDSS: Sloan Digital Sky Survey) supernova searches will improve our limits on the size of - or possibly detect - possible correlations also at high redshift at the per cent level in the near future. With data from the proposed SNAP ( SuperNova Acceleration Probe) satellite, we will be able to detect the induced correlations from gravitational lensing on type Ia peak magnitudes on scales less than a degree.