New statistical tests applied on the four-year COBE-DMR maps

We apply new statistical tests on the four-year 53 GHz DMR data and show th at there is excessive probability for the existence of coherent temperature discontinuities hidden in the CMB maps around the galactic poles. Such dis continuities could have been produced by long strings in out horizon. Compa ring Monte-Carlo simulations with the 53 GHz DMR maps we find that the prob ability for the existence of a coherent discontinuity with amplitude 0.2 x (delta T/T)(rms) superposed on the Gaussian fluctuations is more than doubl e the corresponding probability when no discontinuity is present. This resu lt cannot be used as a detection because the DMR value of the introduced st atistical variable MSD is consistent with a pure Gaussian map at a 20% leve l. However, when combined with the recent findings of Ferreira et al.(1) it points out that the confidence by which the COBE maps are assumed to be Ga ussian should probably be reduced.