Galaxy UGC7321 has the highest signal to noise ratio for the [ <span style="font-variant:small-caps;">HI</span> ]{} data from our sample. The galaxy was previously modelled by @OBrien2010D, who found that the halo flattening $q$ was round ($q=1.0\pm0.1$). Their modelling strategy consisted of a two-pass scheme, in which they first performed a rotation curve decomposition, and only then performed a separate fit to the vertical force gradient. This second fit however failed, and the authors had to drastically deviate from the results from the rotation curve decomposition, and use a very low mass stellar disc, in order to reproduce the observed vertical force gradient. We have performed an inspection of the codes used by in the analysis of @OBrien2010D. It appears there was a restriction which allowed only models with $q\leq1$ and it would have been impossible for them to fit a prolate halo.

@Banerjee2010A also analysed [UGC7321]{} and found a spherical halo. These authors assumed a constant velocity dispersion, or at most a decreasing gradient, in their work, and use a different potential than us.

In Figure \[fig:UGC7321rotation\], we demonstrate our own rotation curve decomposition of this galaxy, and in Figure \[fig:UGC7321zforce\] we show the vertical force gradient decomposition. Rather than 