Milky Way Mass Models and MOND

2008/04/08 by Stacy S. McGaugh, Stacy McGaugh · 4 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Computational astrophysics #Galaxy #Galaxy rotation curve #Luminosity #Mass distribution #Milky Way #Rotation (mathematics) #Scientific Research and Discoveries #Solar mass #Stellar, planetary, and galactic studies #astro-ph

paper · pdf · doi:10.1086/589148

published as Astrophys.J.683:137-148,2008 · Accepted for publication in the Astrophysical Journal. 31 pages including 8 figures and 3 tables

arxiv created 2008/04/08 · openalex publication_date 2008/08/07 · arxiv updated 2010/11/11 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05

Abstract

Using the Tuorla-Heidelberg model for the mass distribution of the Milky Way, I determine the rotation curve predicted by MOND (modified Newtonian dynamics). The result is in good agreement with the observed terminal velocities interior to the solar radius and with estimates of the Galaxy's rotation curve exterior thereto. There are no fit parameters: given the mass distribution, MOND provides a good match to the rotation curve. The Tuorla-Heidelberg model does allow for a variety of exponential scale lengths; MOND prefers short scale lengths in the range 2.0 kpc ≲ R d ≲ 2.5 kpc. The favored value of R d depends somewhat on the choice of interpolation function. There is some preference for the "simple" interpolation function as found by Famaey & Binney. I introduce an interpolation function that shares the advantages of the simple function on galaxy scales while having a much smaller impact in the solar system. I also solve the inverse problem, inferring the surface mass density distribution of the Milky Way from the terminal velocities. The result is a Galaxy with "bumps and wiggles" in both its luminosity profile and rotation curve that are reminiscent of those frequently observed in external galaxies.

Citations

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Cited by

• Radial Acceleration Relation in Rotationally Supported Galaxies
• Probing the radial acceleration relation and the strong equivalence principle with the Coma cluster ultra-diffuse galaxies
• Sedna and the cloud of comets surrounding the solar system in Milgromian dynamics
• Resolving the timing problem of the globular clusters orbiting the Fornax dwarf galaxy