Morphological fluctuations of large-scale structure: the PSCz survey

. In a follow–up study to a previous analysis of the IRAS 1.2Jy catalogue, we quantify the morphological fluctuations in the PSCz survey. We use a variety of measures, among them the family of scalar Minkowski functionals. We confirm the existence of significant fluctuations that are discernible in volume–limited samples out to 200 h − 1 Mpc. In contrast to earlier findings, comparisons with cosmological N –body simulations reveal that the observed fluctuations roughly agree with the cosmic variance found in corresponding mock samples. While two–point measures, e.g. the variance of count–in–cells, fluctuate only mildly, the fluctuations in the morphology on large scales indicate the presence of coherent structures that are at least as large as the sample.