| Title | Neutral hydrogen observations of double spiral galaxies. IV. NGC 4618/4625, NGC 4016/4017, NGC 3725/UGC 6528, UGC 725/728, NGC 2336/IC 467. |
| Authors | van Moorsel, G. A. |
| Bibcode | 1983A&AS...54...19V Search ADS ↗ |
| Abstract | Results of a 21 cm HI line study of five binary galaxies observed in the 21 cm HI line with the WSRT are presented. All ten galaxies were detected in HI, and systemic velocities and rotation curves were determined. The results are discussed in terms of a point mass model for the orbital motion in the pair. Only in the case of the pair NGC 4016/4017 a minimum orbital mass was found which did not exceed the sum of the individual masses. For the other four pairs the individual masses are not sufficient to account for the observed radial velocity differences. This suggests the presence of dark matter in the orbiting systems outside the radii of the individual galaxies. In two galaxies, NGC 4625 and NGC 4017, the HI diameter exceeds the optical one by at least a factor 3. In the case of NGC 4017 the HI distribution is very suggestive of interaction with the companion. |
| Objects | 10 Objects Search NED ↙ |
