HI STUDIES OF THE SCULPTOR GROUP GALAXIES .3. NGC-55

A VLA1 study of the H I properties of the Sculptor group galaxy NGC 55 is presented. The H I distribution is found to be nonsymmetrical with respect to the general light distribution and a warp of the H I plane is observed on the northwest side. The total H I flux density of 1522 Jy km s-1 corresponds to an H I mass of 0.9 x 10(9) M.. As for the light distribution, the luminosity profile is well determined over 6 mag in surface brightness. The total blue luminosity of 4.2 x 10(9) L. is much smaller than previously estimated. The rotation curve, derived from a full tilted ring model, rises slowly out to r congruent-to 12' and then stays more or less flat out to r congruent-to 22'. The mass distribution, obtained by fitting a two-component model to the rotation curve, gives a total mass of 1.8 x 10(10) M. at the last point of the rotation curve. This value implies a mass-to-light ratio of (M/L(B))global = 4.3 M./L..