A Cusp-Core like challenge for Modified Newtonian Dynamics

Abstract

We show that Modified Newtonian Dynamics (MOND) predict distinct galactic acceleration curve geometries in $g2$-space - the space of total observed centripetal accelerations $g_{\mathrm{tot}}$ vs the inferred Newtonian acceleration from baryonic matter $g_{\mathrm{N}}$ - and corresponding rotation speed curves: MOND modified gravity predicts cored geometries for isolated galaxies while MOND modified inertia yields neutral geometries, ie. neither cuspy or cored, based on a cusp-core classification of galaxy rotation curve geometry in $g2$-space - rather than on inferred DM density profiles. The classification can be applied both to DM and modified gravity models as well as data and implies a {\it cusp-core} challenge for MOND from observations, for example of cuspy galaxies, which is different from the so-called cusp-core problem of dark matter (DM). We illustrate this challenge by a number of cuspy and also cored galaxies from the SPARC rotation curve database, which deviate significantly from the MOND modified gravity and MOND modified inertia predictions.

30 pages, 7 figures

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Cited by in corpus (1)

• Normalized additional velocity distribution: testing the radial profile of dark matter halos and MOND