The Parkes Multibeam High-Velocity Cloud Survey



The Parkes Radio Telescope is surveying the entire southern sky for neutral hydrogen and is revealing not only new galaxies, but also an abundance of objects known as high-velocity clouds (HVCs). HVCs are concentrations of neutral hydrogen which surround our Galaxy but do not rotate with it.

Since their discovery in 1963, astronomers have speculated as to their possible origin without consensus. The clouds may have originated during our Galaxy's evolution, or they may be leftovers from when our Galaxy and its neighbours formed. One of the reasons we have been unable to determine where the clouds have come from, is their distribution over the southern sky was very poorly known. The Parkes survey for high-velocity clouds is rapidly changing this situation by providing an abundance of detailed information on the clouds' structure and overall kinematic and spatial distribution.

Principal Investigator

Mary E. Putman

Research School of Astronomy & Astrophysics


Brad K. Gibson

Center for Astrophysics and Space Astronomy

University of Colorado

Ken C. Freeman

Research School of Astronomy & Astrophysics


d05 - MDSS



What are the results to date and the future of the work?

The high-velocity cloud survey has already enabled us to reveal the origin of one particular group of HVCs, found leading our neighbouring galaxies, the Magellanic Clouds. These HVCs are debris due to the interaction of the Clouds with the Milky Way, and their discovery has shown us that the Magellanic Clouds are being pulled apart by tidal forces due to the Milky Way. The discovery of the link between the Magellanic Clouds and these HVCs was only made possible by combining a large amount of the survey data into a single image. The MDSS provided rapid access to this large amount of data.

Future work will include the search for further Magellanic debris HVCs and the investigation of the possibility that many of the small HVCs are actually members of our local group of galaxies. As the data continues to come in, it is crucial that we have a method of storing the massive amounts of data. The entire southern sky will eventually need to be imaged and the MDSS allows us to do this in an orderly and time efficient manner.

Appendix A -




M.E. Putman, B. K. Gibson, L. Staveley-Smith, G. Banks, D. Barnes, R. Bhatal, M. Disney, R. Ekers, K.C. Freeman, R. Haynes, P. Henning, H. Jerjen, V. Kilborn, B. Koribalski, D. Malin, J.R. Mould, T. Oosterloo, M. Price, S. Ryder, E. Sadler, I. Stewart, F. Stootman, B. Vaile, R. Webster & A. Wright, "Tidal Disruption of the Magellanic Clouds by the Milky Way, Nature, 394, 1998, 752.

L. Staveley-Smith, S. Kim, M.E. Putman & S. Stanimirovic, Neutral Hydrogen in the Magellanic System, Reviews in Modern Astronomy, Stars and Galaxies, Astronomische Gesellschaft, 11, 1998, 117.

L. T. Gardiner, C. Turfus & M.E. Putman, Numerical Simulation of Asymmetric Spiral Structure in the Large Magellanic Cloud, ApJL, 507, 1998, 35.

B.P. Wakker, B.D. Savage, T. Oosterloo & M.E. Putman, The HI Fine Structure of HVC187 Near NGC3783: Gas in the Leading Bridge of the Magellanic System, in Mt. Stromlo Workshop on High Velocity Clouds, eds. Gibson & Putman, ASP Conf. Series, 166, 302, in press.

M.E. Putman, B.K. Gibson, & L. Staveley-Smith, Evidence for the Magellanic Stream's Tidal Origin, in The Third Stromlo Symposium: The Galactic Halo, eds. Gibson, Axelrod & Putman, ASP Conf. Series, 165, 113, in press.

M.E. Putman & B.K. Gibson, Early Results from the Parkes Multibeam High-Velocity Cloud Survey, in Mt. Stromlo Workshop on High-Velocity Clouds, eds. Gibson & Putman, ASP Conf. Series, 166, 276, in press.

M.E. Putman & B.K. Gibson, The First Results from the Parkes Multibeam High-Velocity Cloud Survey, PASA, 16, in press.

M.E. Putman, B.K. Gibson & L. Staveley-Smith, New HI features of the Magellanic System, in IAU Symposium 190: New Views of the Magellanic Clouds, Victoria, Canada, July 1998, ASP Conf. Series, in press.

R. Webster, V. Kilborn, J. O'Brien, L. Staveley-Smith, M.E. Putman & G. Banks, The Parkes Multibeam Blind HI Survey, in IAU Symposium 171: Low Surface Brightness Galaxies, Cardiff, July 1998, ASP Conf. Series, in press.

- Appendix A