| Title | The spiral galaxy M101. III. Integral properties of several companion galaxies obtained from neutral hydrogen measurements. |
| Authors | Allen, R. J.; van der Hulst, J. M.; Goss, W. M.; Huchtmeier, W. K. |
| Bibcode | 1978A&A....64..359A Search ADS ↗ |
| Abstract | Summary. We present new observations of the total profiles of the neutral hydrogen emission in several galaxies which are considered to be companions of M101. Estimates of the systemic velocity, hydrogen mass, and total mass are obtained for each galaxy and a discussion of the inaccuracies is given. Such uncertainties have a considerable influence in the computation of the dynamical parameters of a group of galaxies. Finally, new evidence is presented in favour of a physical association between M101 and the luminosity class IV-V galaxy N5477; the velocity of the latter galaxy lies within 15 km 1 of the nearby gas associated with M101 itself. In addition an extension of a faint H I arm in the outer regions of M101 is found near N5477. Using the calibration of H ii region sizes in luminosity class IV-V galaxies as determined by Sandage and Tammann, the distance to M101 based only on its proximity to N5477 is about 7 Mpc. words: galaxies - clusters of galaxies - 21-cm radiation |
| Objects | 11 Objects Search NED ↙ |
