Results of an all-sky high-frequency Einstein@Home search for continuous gravitational waves in LIGO’s fifth science run

We present results of a high-frequency all-sky search for continuous gravitational waves from isolated compact objects in LIGO's fifth science run (S5) data, using the computing power of the Einstein@Home volunteer computing project. This is the only dedicated continuous gravitational wave search that probes this high-frequency range on S5 data. We find no significant candidate signal, so we set 90% confidence level upper limits on continuous gravitational wave strain amplitudes. At the lower end of the search frequency range, around 1250 Hz, the most constraining upper limit is $5.0\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}24}$, while at the higher end, around 1500 Hz, it is $6.2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}24}$. Based on these upper limits, and assuming a fiducial value of the principal moment of inertia of ${10}^{38}\text{ }\text{ }\mathrm{kg}\text{ }{\mathrm{m}}^{2}$, we can exclude objects with ellipticities higher than roughly $2.8\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}7}$ within 100 pc of Earth with rotation periods between 1.3 and 1.6 milliseconds.