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A&A Supplement series, Vol. 129, April II 1998, 313-328

Received September 4; accepted September 22, 1997

Structure and stellar content of dwarf galaxiesgif

I. B and R photometry of dwarf galaxies in the M 81 group

T. Bremnes tex2html_wrap1808 - B. Binggeli tex2html_wrap1808 - P. Prugniel tex2html_wrap1812

Send offprint request: T. Bremnes, e-mail: bremnes@astro.unibas.ch

tex2html_wrap1814  Astronomical Institute, University of Basel, Venusstrasse 7, CH-4102 Binningen, Switzerland
tex2html_wrap1816  Observatoire de Lyon, F-64561 St. Genis-Laval Cedex, France

Abstract:

We have carried out CCD photometry in the Cousins B and R bands of 25 dwarf galaxy members and suspected members of the M 81 group of galaxies. Based on azimuthally averaged brightness profiles we have derived total magnitudes, effective radii, effective surface brightnesses, as well as galaxy diameters at various isophotal levels in both photometric bands. Best-fitting exponential parameters and B - R colour gradients are also given for these galaxies. The data will be interpreted, along with those of another supplementary paper, in Paper III of this series (to appear in the main journal).

In two appendices we discuss the nature of a clustering of unusual low-surface brightness objects in the south-east corner of the M 81 group and show the luminosity function of its presently known members.

keywords: galaxies: general -- galaxies: fundamental parameters -- galaxies: photometry -- galaxies: irregular -- galaxies: clusters: M 81 group





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