Dwarf spheroidals in MOND

2008/04/23 by G. W. Angus, Garry W. Angus · 7 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Dwarf galaxy #Dwarf galaxy problem #Dwarf spheroidal galaxy #Electrical and Electromagnetic Research #Galaxies: Formation, Evolution, Phenomena #Galaxy #Local Group #Milky Way #Modified Newtonian dynamics #RADIUS #Ram pressure #astro-ph

paper · pdf · doi:10.1111/j.1365-2966.2008.13351.x

9 pages, 3 figures, 1 table. Accepted for publication in MNRAS

arxiv created 2008/04/23 · openalex publication_date 2008/06/04 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05

Abstract

We take the line of sight velocity dispersions as functions of radius for 8 Milky Way dwarf spheroidal galaxies and use Jeans analysis to calculate the mass-to-light ratios (M/L) in Modified Newtonian Dynamics (MOND). Using the latest structural parameters, distances and variable velocity anisotropy, we find 6/8 dwarfs have sensible M/L using only the stellar populations. Sextans and Draco, however, have M/L=9.2_-3.0^+5.3 and 43.9_-19.3^+29.0 respectively, which poses a problem. Apart from the need for Sextans' integrated magnitude to be reviewed, we propose tidal effects intrinsic to MOND, testable with numerical simulations, but fully orbit dependant, which are disrupting Draco. The creation of the Magellanic Stream is also re-addressed in MOND, the scenario being the stream is ram pressure stripped from the SMC as it crosses the LMC.

Citations

• A modification of the Newtonian dynamics as a possible alternative to the hidden mass hypothesis
• Two-body relaxation in modified Newtonian dynamics
• Observed Properties of Dark Matter: dynamical studies of dSph galaxies
• Milky Way potentials in cold dark matter and MOdified Newtonian Dynamics. Is the Large Magellanic Cloud on a bound orbit?
• The velocity distribution of Sloan Digital Sky Survey satellites in Modified Newtonian Dynamics
• A photometrically and kinematically distinct core in the Sextans dwarf spheroidal galaxy
• The distance to the Leo I dwarf spheroidal galaxy from the red giant branch tip
• Galaxy merging in modified Newtonian dynamics

Cited by

• Constraining MOND using the vertical motion of stars in the solar neighbourhood
• Verlinde’s emergent gravity versus MOND and the case of dwarf spheroidals
• ANDROMEDA DWARFS IN LIGHT OF MODIFIED NEWTONIAN DYNAMICS
• The abundance of galaxy clusters in modified Newtonian dynamics: cosmological simulations with massive neutrinos
• Dwarf galaxy planes: the discovery of symmetric structures in the Local Group
• Environment-dependent dark sector
• Gravitational Anomalies Signaling the Breakdown of Classical Gravity

Related

• The mass distribution of dwarf spheroidal galaxies from stellar kinematics: Draco, Ursa Minor and Fornax
• THE STELLAR STRUCTURE AND KINEMATICS OF DWARF SPHEROIDAL GALAXIES FORMED BY TIDAL STIRRING
• Mass models of disk galaxies from the DiskMass Survey in MOND
• Light-weight Local Group Dwarf Spheroidal Galaxies
• The Kinematics of Dwarf Spheroidal Galaxies