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We calculate the two-, three- and (for the first time) four-point correlationfunctions of the COBE-DMR 4-year sky maps, and search for evidence ofnon-Gaussianity by comparing the data to Monte Carlo-simulations of thefunctions. The analysis is performed for the 53 and 90 GHz channels, and fivelinear combinations thereof. For each map, we simulate an ensemble of 10,000Gaussian realisations based on an a priori best-fit scale-invariantcosmological power spectrum, the DMR beam pattern and instrument-specific noiseproperties. Each observed COBE-DMR map is compared to the ensemble using asimple chi^2 statistic, itself calibrated by simulations. In addition, underthe assumption of Gaussian fluctuations, we find explicit expressions for theexpected values of the four-point functions in terms of combinations ofproducts of the two-point functions, then compare the observed four-pointstatistics to those predicted by the observed two-point function, using aredefined chi^2 statistic. Both tests accept the hypothesis that the DMR mapsare consistent with Gaussian initial perturbations.Comment: 7 pages, 2 figures, accepted by A&A; Several references added, three  new paragraphs with additional information and several typographical details  fixe

The N-point correlation functions of the COBE-DMR maps revisited