Testing homogeneity of the galaxy distribution in the SDSS using Renyi entropy

We analyze a set of volume limited sample of galaxies from the SDSS to study the issue of cosmic homogeneity. We use the Renyi entropy of different order to probe the inhomogeneties present in the galaxy distributions. We also calculate the Renyi diveregence to quantify the deviations of the galaxy distribution from a homogeneous Poisson distribution on different length scales. We separately carry out the analysis using the overlapping spheres and the independent voxels. Our analysis suggests that the scale of homogeneity is underestimated in the smaller galaxy samples due to the suppression of inhomogeneities by the overlapping of the measuring speheres. We find that an analysis with the independent voxels and/or use of a significantly larger galaxy sample can help to circumvent or mitigate this problem. Combining the results from these analyses, we find that the galaxy distribution in the SDSS becomes homogeneous on a length scale beyond 140 h(-1) Mpc.

Automated summary

The study investigates the issue of cosmic homogeneity in galaxies from the SDSS using Renyi entropy and divergence. It finds that the scale of homogeneity is underestimated in smaller samples, but can be improved with the use of independent voxels and larger samples. The analysis concludes that the galaxy distribution in the SDSS becomes homogeneous on a length scale beyond 140 h(-1) Mpc.