Loss of mass and stability of galaxies in modified newtonian dynamics

Journal article

Authors/Editors

Angus, Garry

Research Areas

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Publication Details

Author list: Wu XF, Zhao HS, Famaey B, Gentile G, Tiret O, Combes F, Angus GW, Robin AC

Publisher: American Astronomical Society

Place: BRISTOL

Publication year: 2007

Journal: The Astrophysical Journal (0004-637X)

Journal acronym: ASTROPHYS J

Volume number: 665

Issue number: 2

Start page: L101

End page: L104

ISSN: 0004-637X

eISSN: 1538-4357

Languages: English-Great Britain (EN-GB)

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Abstract

The self-binding energy and stability of a galaxy in MOND-based gravity are curiously decreasing functions of its center-of-mass acceleration (of the order of 10(-12) to 10(-10) m s(-2)) toward neighboring mass concentrations. A tentative indication of this breaking of the strong equivalence principle in field galaxies is the RAVE-observed escape speed in the Milky Way. Another consequence is that satellites of field galaxies will move on nearly Keplerian orbits at large radii (100-500 kpc), with a declining speed below the asymptotically constant naive MOND prediction. But the consequences of an environment-sensitive gravity are even more severe in clusters, where member galaxies accelerate fast; no dark halo-like potential is present to support galaxies, meaning that extended axisymmetric disks of gas and stars are likely unstable. These predicted reappearances of asymptotic Keplerian velocity curves and disappearances of "stereotypic galaxies" in clusters are falsifiable with targeted surveys.

Keywords

Dark matter, galaxies : kinematics and dynamics, galaxies : structure, gravitation

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