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A&A Supplement Ser., Vol. 124, July 1997, 189-196

Received August 22; accepted November 4, 1996

Absolute stellar proper motions with reference to galaxies of the M81 group

M. Odenkirchen tex2html_wrap1190 - P. Brosche tex2html_wrap1192 - F. Börngen tex2html_wrap1194 - H. Meusinger tex2html_wrap1196 - R. Ziener tex2html_wrap1198

Send offprint request: M. Odenkirchen

tex2html_wrap1200  Sternwarte der Universität Bonn, Auf dem Hügel 71, D-53121 Bonn, Germany
tex2html_wrap1202  Thüringer Landessternwarte Tautenburg, Sternwarte 5, D-07778 Tautenburg, Germany


We report on the measurement of absolute proper motions of stars of magnitude 7 to 14.5 in a tex2html_wrap_inline1178 field in the region of the M81 group of galaxies. This work is part of the Bonn program for the extragalactic link of Hipparcos. The proper motions were determined from a collection of photographic plates covering the time interval from 1894 to 1994. The absolute reference system for the proper motions is represented by the galaxies M81, M82 and NGC3077, for which accurate optical reference positions were obtained by means of an image cross-correlation technique. For the majority of stars, the internal proper motion accuracy is better than 1mas/a. The precision of the realization of the absolute system is found to be around 1mas/a. In total, our measurements yield absolute proper motions for 24 Hipparcos stars and positions, proper motions and photometry for 330 additional stars including a number of visual binaries and high proper motion stars. Among the latter one G-type subdwarf is identified. The results are relevant as a contribution to the Hipparcos link, but also as a database for kinematic investigations.

keywords: galaxies: M81 -- astrometry -- reference systems -- catalogs

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