| Abstract | The neutral hydrogen content of 49 galaxies has been measured with the radiotelescope. A least- squares method of reduction has been used, yielding best values of the parameters of the 21-cm line proffle, together with their errors. The systemic velocities agree with optical measurements. The velocity of the Sun with respect to the local Universe, established from the radial velocities of 37 galaxies less than 6 Mpc away from the Sun but outside the Local Group, is V0 = 250 + 40 km -1 towards l = 130 + 20 , b" = -9 + 8 Hubble's constant isfoundtobeH= 77+ 11kms- -1. Correlations have been found between several physical parameters. Particularly, a relation between the distance, the angular diameter, and the width of the 21-cm line proffle of a galaxy allows determination of distances within a factor 1.7; this method is used to determine distances of 6 galaxies. The correlations found between 1/a and the type, v, and between M111/L* and T are interpreted for spiral galaxies in a simple model, in which hydrogen is supposed to be distributed uniformly in a disk of diameter a and mean thickness a e. The assumption of a rate of star formation proportional to the square of the gas volumic density leads to estimates for the variation of relative thickness, e, and of average hydrogen density with type. Key words: galaxies - radio measurements: 21-cm neutral |
