kpc region because some of our [[H]{}[<span style="font-variant:small-caps;">i</span> ]{}]{}rich galaxies have large [[H]{}[<span style="font-variant:small-caps;">i</span> ]{}]{}disks extending to $\sim$ 100 kpc. The radial range is always confined within the full-width-half-power of the primary beam. Most of the candidates have [[H]{}[<span style="font-variant:small-caps;">i</span> ]{}]{}masses (absolute values for the negative candidates) within the range of $4.0\times10^6\ms$ and $1.4\times10^8\ms$ (5 and 95 percentiles of the distribution).

The ensemble of all positive and negative candidate detections results in a net positive [[H]{}[<span style="font-variant:small-caps;">i</span> ]{}]{}signal in the environment around Bluedisk galaxies. We show this by calculating for each cube the accumulative [[H]{}[<span style="font-variant:small-caps;">i</span> ]{}]{}mass ($\mHIcand$) by summing up all negative and positive candidates in the volume defined above. To further improve the signal-to-noise ratio, we calculate the average $\mHIcand$ of the 40 cubes. We calculate the error bars as a combination of the variation over the data cubes (var1) and the mean variation within a data cube (var2). The variation over the data cubes (var1) is calculated through a standard bootstrapping procedure. Taking the whole sample of 40 cubes for example, we randomly select 40 cubes from the sample (repetition allowed) and calculate the average $\mHIcand$. We repeat this step for 1000 times and obtain a distribution 