Milky Way potentials in cold dark matter and MOdified Newtonian Dynamics. Is the Large Magellanic Cloud on a bound orbit?

Xufen Wu, Benoit Famaey, Gianfranco Gentile, Hagai Perets, Hongsheng Zhao

Research output: Contribution to journalArticlepeer-review

Abstract

We compute the Milky Way potential in different cold dark matter (CDM) based models, and compare these with the MOdified Newtonian Dynamics (MOND) framework. We calculate the axial ratio of the potential in various models, and find that isopotentials are less spherical in MOND than in CDM potentials. As an application of these models, we predict the escape velocity as a function of the position in the Galaxy. This could be useful in comparing with future data from planned or already-underway kinematic surveys (RAVE, SDSS, SEGUE, SIM, Gaia or the hypervelocity stars survey). In addition, the predicted escape velocity is compared with the recently measured high proper motion velocity of the Large Magellanic Cloud (LMC). To bind the LMC to the Galaxy in a MOND model, while still being compatible with the RAVE-measured local escape speed at the Sun's position, we show that an external field modulus of less than 0.03a(0) is needed.

Original languageEnglish
Pages (from-to)2199-2208
Number of pages10
JournalMonthly Notices of the Royal Astronomical Society
Volume386
Issue number4
Early online date10 Apr 2008
DOIs
Publication statusPublished - 1 Jun 2008

Keywords

  • gravitation
  • Galaxy : kinematics and dynamics
  • dark matter
  • N-BODY SIMULATIONS
  • HYPERVELOCITY STARS
  • ROTATION CURVE
  • BLACK-HOLE
  • VELOCITY DISPERSION
  • GALACTIC-CENTER
  • DWARF GALAXIES
  • PROPER MOTION
  • DISC GALAXIES
  • HIDDEN MASS

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