Another flattened dark halo: Polar ring galaxy A0136−0801

Knowledge of the shape of dark matter halos is critical to our understanding of galaxy formation, dynamics, and of the nature of dark matter itself. Polar ring galaxies (PRGs)—early‐type galaxies defined by their outer rings of gas, dust and stars on orbits nearly perpendicular to those of the central host—provide a rare probe of the vertical‐to‐radial axis ratio (qρ=c/a) of dark halos. We present a Fabry‐Perot velocity field for the Hα gas in the kinematically‐confirmed PRG A0136−0801. By comparing ring orbits evolved in a generalized mass model to the observed ring velocity field and morphology of A0136−0801, we conclude that qρ∼0.5 and rule out a spherical geometry.