The intricate link between galaxy dynamics and intrinsic shape (or why so-called prolate rotation is a misnomer)

Abstract

Many recent integral integral field spectroscopy (IFS) survey teams have used stellar kinematic maps combined with imaging to statistically infer the underlying distributions of galaxy intrinsic shapes. With now several IFS samples at our disposal, the method, which was originally proposed by M. Franx and collaborators in 1991, is gaining in popularity, having been so far applied to ATLAS3D, SAMI, MANGA and MASSIVE. We present results showing that a commonly assumed relationship between dynamical and intrinsic shape alignment does not hold in Illustris, affecting our ability to recover accurate intrinsic shape distributions. A further implication is that so-called "prolate rotation", where the bulk of stars in prolate galaxies are thought to rotate around the projected major axis, is a misnomer.

4 pages, 1 figure, IAU353 Proceedings

References in corpus (11)

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• Properties of galaxies reproduced by a hydrodynamic simulation
• Introducing the Illustris Project: the evolution of galaxy populations across cosmic time
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• The SLUGGS Survey: stellar kinematics, kinemetry and trends at large radii in 25 early-type galaxies
• The origin and properties of massive prolate galaxies in the Illustris simulation
• The SAMI Galaxy Survey: the intrinsic shape of kinematically selected galaxies
• The Next Generation Virgo Cluster Survey. VII. The intrinsic shapes of low-luminosity galaxies in the core of the Virgo cluster, and a comparison with the Local Group
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• The effects of environment on the intrinsic shape of galaxies