Elliptical galaxies spinning on end

Abstract

Galaxy Structure Most elliptical galaxies have a flattened shape and rotate around their shortest axis, like a wheel. However, some galaxies, known as prolate rotators, are elongated and spin around their longest axis, like a spindle. Tsatsi et al. searched a large survey of galaxy kinematics to discover eight previously unknown examples. They estimate that around 10% of elliptical galaxies are prolate rotators, but the fraction is higher at higher masses. They use simulations to show that prolate rotators can form if two massive spiral galaxies merge in a polar orientation, potentially explaining the evolutionary history of these systems. Astron. Astrophys. 606 , A62 (2017).