The high-energy galactic tau neutrino flux and its atmospheric background

We compare the tau neutrino flux arising from the galaxy and the earth atmosphere for ${10}^3\le E\mathrm{/}GeV\le {10}^{11}$. The intrinsic and oscillated tau neutrino fluxes from both sources are considered. We find that, for $E\geq 10^3$GeV,theoscillated$\nu_{\tau}$ flux along the galactic plane dominates over the maximal intrinsic atmospheric ${\nu }_{\tau }$ flux, i.e., the flux along the horizontal direction. We also briefly comment on the prospects for observing these high-energy tau neutrinos.