The aperture for UHE tau neutrinos of the Auger fluorescence detector using a Digital Elevation Map

We perform a new study of the chances of the fluorescence detector (FD) at the Pierre Auger Observatory to detect the tau leptons produced by Earth-skimming ultra high energy ν's. We present a new and more detailed evaluation of the effective aperture of the FD that considers a reliable fiducial volume for the experimental set up. In addition, we take into account the real elevation profile of the area near Auger. We find a significant increase in the number of expected events with respect to the predictions of a previous semi-analytical determination, and our results show the enhancement effect for neutrino detection from the presence of the near mountains.