2013ApJ...773L...4V
Constraints on the Shape of the Milky Way Dark Matter Halo from the Sagittarius Stream
Vera-Ciro, Carlos ( Department of Astronomy, University of Wisconsin, 2535 Sterling Hall, 475 N. Charter Street, Madison, WI 53076, USA ; Kapteyn Astronomical Institute, University of Groningen, P.O. Box 800, 9700 AV Groningen, The Netherlands; ); Helmi, Amina ( Kapteyn Astronomical Institute, University of Groningen, P.O. Box 800, 9700 AV Groningen, The Netherlands ) show affiliations
The Astrophysical Journal Letters, Volume 773, Issue 1, article id. L4, 5 pp. (2013).
Published in Aug 2013
We propose a new model for the dark matter halo of the Milky Way that fits the properties of the stellar stream associated with the Sagittarius dwarf galaxy. Our dark halo is oblate with qz = 0.9 for r <~ 10 kpc, and can be made to follow the Law & Majewski model at larger radii. However, we find that the dynamical perturbations induced by the Large Magellanic Cloud on the orbit of Sgr cannot be neglected when modeling its streams. When taken into account, this leads us to constrain the Galaxy's outer halo shape to have minor-to-major axis ratio >(c/a)Φ = 0.8 and intermediate-to-major axis ratio (b/a)Φ = 0.9, in good agreement with cosmological expectations.
Keywords:
Free Keywords: Astrophysics - Galaxy Astrophysics; Galaxy: halo; Local Group; galaxies: dwarf; galaxies: interactions
Astronomy: Galaxy: halo; Local Group; galaxies: dwarf; galaxies: interactions
arXiv: Astrophysics - Galaxy Astrophysics
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