et al. 2010), allowing a multi-wavelength analysis. Radio 21 cm synthesis data were obtained with the Westerbork Synthesis Radio Telescope (WSRT), with the main goal of observing the [[H]{}[<span style="font-variant:small-caps;">i</span> ]{}]{}emission line. In this paper, we make use of the [[H]{}[<span style="font-variant:small-caps;">i</span> ]{}]{}data cubes optimised for high sensitivity at lower resolution, which are produced with Robust 0 weighting and 30$"$ tapering. The data cubes have a typical rms of 0.37 mJy beam$^{-1}$, a typical beam size of 38$'' \times 36''$ and a velocity resolution of 12.3 km/s (after Hanning smoothing), which provides sufficient sensitivity to detect point sources down to an [[H]{}[<span style="font-variant:small-caps;">i</span> ]{}]{}mass of a few $10^8\ms$. The primary beam has a FWHM (full-width-at-half-maximum) of $\sim0.5\degr$, corresponding to a $\sim1$ Mpc sky region around the target galaxies, hence the data is very suitable for studying the relatively large-scale [[H]{}[<span style="font-variant:small-caps;">i</span> ]{}]{}environment around the central sources. The details of the primary beam correction are discussed in E.Wang et al.(2015).

Following Paper I, we use the 42 isolated target galaxies for this study. Hence, the local environment is different from groups or clusters, where the dominant process is gas stripping rather than accretion. We further exclude two galaxies (galaxy 14 and 