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On the stability of tidal streams

Schneider, Aurel ; Moore, Ben

In: Monthly Notices of the Royal Astronomical Society, 2011, vol. 415, no. 2, p. 1569-1576

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    Title
    • On the stability of tidal streams
    Author
    • Schneider, Aurel. Institute for Theoretical Physics, University of Zurich, Zurich, Switzerland
    • Moore, Ben. Institute for Theoretical Physics, University of Zurich, Zurich, Switzerland
    Document Type
    • Postprint
    OAI-PMH Identifier
    • oai:doc.rero.ch:296167
    Summary
    We explore the stability of tidal streams to perturbations, motivated by recent claims that the clumpy structure of the stellar streams surrounding the globular cluster Palomar 5 are the result of gravitational instability. We calculate the Jeans length of tidal streams by treating them as a thin expanding cylinder of collisionless matter. We also find a general relation between the density and the velocity dispersion inside a stream, which is used to determine the longitudinal Jeans criterion. Our analytic results are checked by following the time evolution of the phase space density within streams using numerical simulations. We conclude that tidal streams within our Galactic halo are stable on all length scales and over all time-scales