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A Magellanic origin for the warp of the Galaxy

Abstract
We show that a Magellanic Cloud origin for the warp of the Milky Way can explain most quantitative features of the outer H I layer recently identified by Levine et al. We construct a model, similar to that presented by Weinberg in 1998, that produces distortions in the dark matter halo, and we calculate the combined effect of these dark halo distortions and the direct tidal forcing by the Magellanic Clouds on the disk warp in the linear regime. The interaction of the dark matter halo with the disk and resonances between the orbit of the Clouds and the disk account for the large amplitudes observed for the vertical m = 0, 1, and 2 harmonics. The observations lead to six constraints on warp-forcing mechanisms, and our model reasonably approximates all six. The disk is shown to be very dynamic, constantly changing its shape as the Clouds proceed along their orbit. We discuss the challenges to MOND posed by the observations.
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2006-01-01
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