Search for diffuse neutrino point sources using a multipole analysis in IceCube

The IceCube Neutrino Observatory has recently found evidence for a diffuse, astrophysical, high-energy neutrino flux. To resolve this diffuse flux into point-like sources is one of the key tasks of IceCube within the next years. We present a multipole analysis which is based on the expansion of a three years data sample of the northern hemisphere into spherical harmonics looking for a characteristic fingerprint of neutrino point-sources in the expansion coefficients. An appropriate test-statistic is defined to distinguish a possible signal contribution from pure atmospheric neutrino background. Since no astrophysical contribution is found in the data, conclusions are drawn with respect to the recently measured astrophysical flux and limits on the resulting possible number of neutrino point-sources are calculated for different energy spectra. Additionally, a simple method for converting these limits to a wide range of theoretical model predictions of the source count distribution is presented.