Sec. \[s:SPS\]). This barycentric resampling method will be used extensively in searches of Advanced LIGO and Virgo detector data.

This article is structured as follows: In Sec. \[s:searches\] we present the method, implementation, and results of the search. The upper limits set in the absence of a signal are presented in Sec. \[s:uls\], and the results are discussed in Sec. \[s:disc\].

Searches {#s:searches}
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Data selection
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The sixth initial LIGO science run (S6) extended from July 7 2009 21:00:00 UTC (GPS 931035615) to October 21 2010 00:00:00 UTC (GPS 971654415) and included two initial LIGO detectors with 4-km arm lengths, H1 at near Hanford, Washington and L1 at near Livingston, Louisiana.

After optimization at fixed computing cost determined an optimum coherence time of 9.2 days (see Sec. \[s:SPS\]), two different methods were used to determine which data would be searched, producing two different 9.2-day stretches. Both were searched, allowing for the comparison of search results between them.

The first method was to look for the most sensitive average data from S6. This was done by taking nine week-long data samples from each detector spaced roughly 55 days apart, giving nine evenly spaced weeks throughout the duration of S6. The 