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Session 65 - New Views of the Magellanic Clouds - II.
Oral session, Wednesday, June 12
Historical Society,

[65.10] The Proper Motion of the SMC

M. Irwin (RGO), S. Demers (U. Montreal), W. Kunkel (Las Campanas)

AAT and CTIO 4m photographic plates covering a baseline of 15-20 years have been used to measure the absolute proper motion of the Small Magellanic Cloud (SMC). Three fields, two centred on the western SMC clusters Lindsay 1 and Kron 3, and the other in a field located near Kron 3, were selected because of the availability of suitable first epoch plates taken in the 1970's. Eastern SMC fields were not considered due to the likely chaotic motion, reflected in the morphological appearance of the SMC in this region. The plates were digitised and processed using the APM facility in Cambridge. An inertial reference frame was constructed by defining a coordinate system based on \approx1000 faint background galaxies visible on both first and second epoch plates. Colour-magnitude diagrams were then used to select out probable SMC members, generally giant, sub-giant branch and red horizontal branch stars and estimate the Galactic foreground contamination. Combining all the sources of systematic and random error yields a proper motion accurate to \pm50 km/,

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