potential the stream is traversing. @Helmi2004A analysed the stream of Sagittarius, as found in the 2MASS survey, around the Galaxy and found that the data best fits a model with a prolate shape, with an axis ratio of 5/3. In a similar fashion, only further out, do the satellites of the Galaxy offer such a tracer. Globular cluster NGC5466 was modelled by @Lux2012A and found to favor an oblate or triaxial halo, while excluding spherical and prolate haloes with a high confidence. The stellar stream has been reanalysed by @VeraCiro2013, who report an oblate halo with $q=0.9$ for $r\leq10$kpc.

Gravitational lensing offers another measure of the vertical gravitational potential. Strong lensing uses the Einstein lens of background sources around a single galaxy or cluster. By modelling the lens, it is possible to create a detailed mass map of the system. By combining this with gas and stellar kinematics, it is possible to calculate the dark matter mass distribution [@Treu2010A]. For example, @Barnabe2012A applied this method to lensed galaxy SDSS J2141, to find a slightly oblate halo ($q = 0.91^{+0.15}_{-0.13}$).

Weak lensing lacks the clear gravitation lens seen in strong lensing. As such, it is unable to measure the halo of 