Letters to Nature

Nature 394, 752-754 (20 August 1998) | doi:10.1038/29466; Received 16 March 1998; Accepted 9 July 1998

Tidal disruption of the Magellanic Clouds by the Milky Way

M. E. Putman1, B. K. Gibson1, L. Staveley-Smith2, G. Banks3, D. G. Barnes2, R. Bhatal5, M. J. Disney3, R. D. Ekers2, K. C. Freeman1, R. F. Haynes2, P. Henning6, H. Jerjen1, V. Kilborn4, B. Koribalski2, P. Knezek7, D. F. Malin8, J. R. Mould1, T. Oosterloo9, R. M. Price2, S. D. Ryder10, E. M. Sadler11, I. Stewart2, F. Stootman5, R. A. Vaile5,12, R. L. Webster4 & A. E. Wright2

  1. Mount Stromlo & Siding Spring Observatories, Australian National University, Weston Creek PO, Weston, ACT 2611, Australia
  2. Australia Telescope National Facility, CSIRO, PO Box 76, Epping, New South Wales 2121, Australia
  3. University of Wales, Cardiff, Department of Physics & Astronomy, PO Box 913, Cardiff CF2 3YB, UK
  4. University of Melbourne, School of Physics, Parkville, Victoria 3052, Australia
  5. University of Western Sydney Macarthur, Department of Physics, PO Box 555, Campbelltown, New South Wales 2560, Australia
  6. University of New Mexico, Department of Physics & Astronomy, 800 Yale Blvd. NE, Albquerque, New Mexico 87131, USA
  7. The Johns Hopkins University, Department of Physics & Astronomy, 34th & North Charles Streets, Baltimore, Maryland 21218, USA
  8. Anglo-Australian Observatory, PO Box 296, Epping, New South Wales 2121, Australia
  9. Istituto di Fisica Cosmica, via Bassini 15, I-20133 Milano, Italy
  10. Joint Astronomy Center, 660 North Aohoku Place, Hilo, Hawaii 96720, USA
  11. University of Sydney, Astrophysics Department, School of Physics, A28, Sydney, New South Wales 2006, Australia
  12. Deceased.

Correspondence to: M. E. Putman1 Correspondence should be addressed to M.E.P. (e-mail: Email: putman@mso.anu.edu.au).

Interactions between galaxies are common, and influence physical properties such as the global morphology and star-formation rate1 (Hubble type). Galaxies can interact in many different ways: they can merge together; they can pass through each other, with gas being stripped from the smaller of the two and compressed in the larger; and they can interact gravitationally2 (including, for example, tides in clusters). The relative importance of these mechanisms is often not clear, as the strength of each depends on poorly known parameters such as the density, extent and nature of the dark-matter haloes that surround galaxies3. A nearby example of a galaxy interaction where the mechanism is controversial is that between our Galaxy and two of its neighbours, the Magellanic Clouds. Here we present the results of an atomic-hydrogen survey that help to elucidate this mechanism. Our data reveal a new stream of gas that lies in the opposite direction to the trailing Magellanic Stream and leads the motion of the Clouds. The existence of both leading and trailing streams supports a gravitational interaction whereby the streams are torn from the bodies of the Magellanic Clouds by tidal forces.