We present the first results in the search for relativistic magnetic monopoles with the IceCube detector, a subsurface neutrino telescope located in the South Polar ice cap containing a volume of 1 km$^{ 3}$. This analysis searches data taken on the partially completed detector during 2007 when roughly 0.2 km$^{ 3}$ of ice was instrumented. The lack of candidate events leads to an upper limit on the flux of relativistic magnetic monopoles of $\Phi_{ \mathrm{ 90%C.L.}}\sim 3\e{ -18}\fluxunits$ for $\beta\geq0.8$. This is a factor of 4 improvement over the previous best experimental flux limits up to a Lorentz boost $\gamma$ below $10^{ 7}$. This result is then interpreted for a wide range of mass and kinetic energy values.
Categories: astro-ph.HE