NGC 5466: a unique probe of the Galactic halo shape

  1. H. Lux1,2,*,
  2. J. I. Read3,4,
  3. G. Lake2,
  4. K. V. Johnston5

Article first published online: 18 MAY 2012

DOI: 10.1111/j.1745-3933.2012.01276.x

Issue

Monthly Notices of the Royal Astronomical Society: Letters

Monthly Notices of the Royal Astronomical Society: Letters

Volume 424, Issue 1, pages L16–L20, July 2012

Additional Information

How to Cite

Lux, H., Read, J. I., Lake, G. and Johnston, K. V. (2012), NGC 5466: a unique probe of the Galactic halo shape. Monthly Notices of the Royal Astronomical Society: Letters, 424: L16–L20. doi: 10.1111/j.1745-3933.2012.01276.x

Author Information

  1. 1

    School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD

  2. 2

    Department of Theoretical Physics, University of Zürich, Winterthurerstr. 190, CH-8057 Zürich, Switzerland

  3. 3

    Institute for Astronomy, Department of Physics, ETH Zürich, Wolfgang-Pauli-Strasse 16, CH-8093 Zürich, Switzerland

  4. 4

    Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH

  5. 5

    Department of Astronomy, Columbia University, Pupin Physics Laboratories, 550 West 120th Street, New York, NY 10027, USA

* E-mail: Hanni.Lux@nottingham.ac.uk

Publication History

  1. Issue published online: 5 JUL 2012
  2. Article first published online: 18 MAY 2012
  3. Accepted 2012 April 25. Received 2012 April 25; in original form 2012 February 10

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Keywords:

  • globular clusters: individual: NGC 5466;
  • Galaxy: halo;
  • Galaxy: kinematics and dynamics;
  • Galaxy: structure

ABSTRACT

Stellar streams provide unique probes of galactic potentials, with the longer streams normally providing the cleaner measurements. In this Letter, we show an example of a short tidal stream that is particularly sensitive to the shape of the Milky Way’s dark matter halo: the globular cluster tidal stream NGC 5466. This stream has an interesting deviation from a smooth orbit at its western edge. We show that such a deviation favours an underlying oblate or triaxial halo (irrespective of plausible variations in the Milky Way disc properties and the specific halo parametrization chosen); spherical or prolate halo shapes can be excluded at a high confidence level. Therefore, more extensive data sets along the NGC 5466 tidal stream promise strong constraints on the Milky Way halo shape.

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