We thank B. Burton and S. West for providing us the HI 21 cm data prior to publication. P.Á. also thanks M. Róyczka for his hospitality at Warsaw University in 1990, and for the discussions about modelling expanding structures. This study has made use of the SIMBAD data base operated at CDS, Strasbourg, France. The authors are indebted to Jan Brand, the referee of this paper, for his invaluable contribution to the improvement of this paper. This work was partly supported by the grants of the Hungarian National Research Fund (OTKA) T4341, T024027, T022946 and F4342.
© European Southern Observatory (ESO) 2000
Online publication: February 9, 2000