| Title | Neutral hydrogen in the normal elliptical galaxy NGC 4278. |
| Authors | Gallagher, J. S.; Knapp, G. R.; Faber, S. M.; Balick, B. |
| Bibcode | 1977ApJ...215..463G Search ADS ↗ |
| Abstract | We report the first convincing detection of neutral hydrogen in a structurally normal elliptical galaxy, NOC 4278 (type El). The observed 21 cm emission-line profile is roughly Gaussian in shape, has a central velocity close to the optical velocity of the galaxy, and has a full width at half- maximum (FWHM) of 470 km s '. If D = 16 Mpc, the H i mass is 7 x 108 M0 and the H mass-to-photographic-luminosity ratio is 0.05 in solar units, a remarkably high value for an elliptical galaxy. The H I is unresolved with a FWHM 10' beam. NOC 4278 is a morphologically normal elliptical galaxy but has an unusually intense compact nuclear radio source as well as a relatively bright nuclear emission-line spectrum. It is not known whether the nuclear activity in NGC 4278 is related in some way to the unusually high H i content. Possible sources for the H i include mass loss from stars or infall from the intergalactic medium. Infall models seem more in accord with the data now available. The present situation is perhaps unstable, and possible evolutionary scenarios are briefly mentioned. Subject headings: galaxies: individual - galaxies: structure - interstellar: matter - radio sources: 21 cm radiation |
| Objects | 1 Objects Search NED ↙ |
