described, 137 are classified as reliable. 42 of the reliable sources lie within a projected distance ($D_{proj}$) of 500 kpc and a systematic velocity difference ($\Delta V_{sys}$) of 500 km$/$s around the primary galaxies. 95$\%$ of them have $\mHI>1.62\times10^8\ms$. All of them can be associated with an optical galaxy down to a $r$ band magnitude of 22 by requiring the centre to be offset by less than the size of the [[H]{}[<span style="font-variant:small-caps;">i</span> ]{}]{}beam. The connection between primary galaxies and these reliable sources (satellite galaxies) is studied in detail in E. Wang et al. (2015). One of the key findings is that the satellites of ${\rm H}{\textsc i}$-excess galaxies ($\Delta_{C13}\fHI>0$; see Sec. 2) have higher [[H]{}[<span style="font-variant:small-caps;">i</span> ]{}]{}excess than the satellites of ${\rm H}{\textsc i}$-normal galaxies ($\Delta_{C13}\fHI<0$). Here we aim to test whether such a connection between the [[H]{}[<span style="font-variant:small-caps;">i</span> ]{}]{}content of galaxies and that of their environment holds also when studying the fainter, candidate [[H]{}[<span style="font-variant:small-caps;">i</span> ]{}]{}sources.

We find 6,369 candidates that lie within a $D_{proj}$ of 100 to 500 kpc and $V_{sys}$ distance of 500 km$/$s from the primary galaxies, and these will serve as the main sample for analysis in what follows. We exclude the inner 100 