Galaxies found in NED with known spectroscopic redshifts in a range of 100′×100′ around Nube and a recession velocity of within 2000 km s⁻¹ of that of the HI detection (i.e. V_helio = 7480 km s⁻¹). The galaxies are colour-coded according to their relative velocity with respect to the potential velocity of Nube. The grey-scale background image is the GBT beam response from Spekkens et al. (2013). The contours indicate where the efficiency drops by the factor indicated on the label, from 0.05% (black) to 50% (light blue). The top horizontal axis indicates the equivalent size in Mpc at a distance of 107 Mpc.