strain histograms of run-averaged (i.e., over all of S6) spectra from each detector, to identify instrumental noise lines which could be responsible. In five of the seven cases, the strain histograms gave clear evidence of an instrumental noise line responsible for the candidate, and in these cases records of prior detector characterization studies were consulted to provide explanations for the noise artifacts. In those cases the artifact is listed in Table  \[CandidateTable\] as well. Two of the artifacts arose from hardware injections at different points in the sky, used to test interferometer response  [@S6CasAFriends].

The remaining two candidates were given another round of followup, with a time shift and extended look performed in data from June 2010, the farthest removed (in the time domain) available data of comparable sensitivity. The large time separation creates a large difference in the Doppler corrections needed to reconstruct an astrophysical source, making these corrections unlikely to reinforce instrumental or environmental artifacts. Both outliers failed to pass the $2\mathcal{F}$ thresholds established by software injections in any of their June tests.

The loudest $2\mathcal{F}$ value expected in the absence of signal depends on the number of templates searched [@Wette2009];[^1] for our search, the largest expected $2\mathcal{F}$ 