The HI observations were conducted on March 27 and 28 2002 with the ATCA in EW367 array configuration (project ID of C1024). The ATCA primary beam is 33.1-arcmin at 1416MHz, which is comparable to the angular distance between the pair of galaxies of ~30.3-arcmin. With a single pointing, the sensitivity at the locations of the galaxies hence drops by a factor of ~1.8, and therefore we had two extra pointings centered on each galaxy in order to keep the desired sensitivity toward the pair. The observing frequency was centered on 1416MHz with a total bandwidth of 8MHz, which is configured into 512 channels, yielding a channel width of 3.3km/s.