The formation of the Magellanic Stream: simulations in a bound orbit

Jonathan Daniel Diaz

    Research output: ThesisMaster's Thesis

    61 Downloads (Pure)


    Bound orbits have traditionally been assigned to the Large and Small Magellanic Clouds (LMC and SMC, respectively) in order to provide a formation scenario for the Magellanic Stream (MS) and its Leading Arm (LA), two prominent neutral hydrogen (HI) features connected to the LMC and SMC. However, Hubble Space Telescope (HST) measurements of the proper motions of the LMC and SMC have challenged the plausibility of bound orbits, causing the origin of the MS to re-emerge as a contested issue. In this thesis, a new tidal model is presented in which structures resembling the bifurcated MS and elongated LA are able to form in a bound orbit consistent with the HST proper motions. The LMC and SMC have remained bound to each other only recently in the model despite being separately bound to the Milky Way for more than 5 Gyr. We nd that the MS and LA are able to form as a consequence of LMC-dominated tidal stripping during the recent dynamical coupling of the LMC and SMC. Next, the model is further re ned by including the e ect of drag from the Galactic hot halo, and the overall e ect on the morphology and kinematics is explored. To accompany this analysis, the drag e ect is also incorporated into a di erent tidal model from the literature. We nd that the drag has three e ects which, although model-dependent, may bring the tidal formation scenario into better agreement with observations: correcting the LA kinematics, reproducing the MS column density gradient, and enhancing the formation of MS bifurcation. We furthermore propose a two-stage mechanism by which the bifurcation forms. In general, the inclusion of drag has a variety of both positive and negative e ects on the global properties of the MS and LA, including their on-sky positions, kinematics, radial distances, and column densities.
    Original languageEnglish
    Publication statusUnpublished - 2011


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