Distribution and motions of atomic hydrogen in lenticular galaxies. VIII. The SO/a galaxies NGC 3619, 3626 and 3900.
Abstract
The S0/a-type galaxies NGC 3619, NGC 3626 and NGC 3900 were mapped at Westerbork in the 21-cm H I line with a spatial resolution of about 30" and a velocity resolution of 40 km s^-1^. Some global properties of the galaxies derived from our observations are summarized in Table 3. NGC 3619, whose optical appearance shows signs of a possible merger or accretion, is somewhat exceptional as its H I extent is considerably smaller than its optical de Vaucouleurs radius R_25_ ~ 0.75 R_25_ at a level of σ_H I_ = 1 M_sun_ pc^-2^. An encounter with the nearby spiral NGC 3625, or merging with a dwarf galaxy, some 0.5 to 1 10^9^ yr ago seem to be reasonable explanations for the optical and H I properties of NGC 3619. A comparison of the global properties of S0/a galaxies, derived from H I synthesis observations, to those of S0s and later-type spirals shows that the H I distribution of S0/a galaxies resembles that of Sa rather than S0 galaxies indicating an internal origin of the H I gas in S0/a galaxies The Tully-Fisher relation and total mass-to-light ratios of S0/a galaxies are similar to those of other types of galaxies (no segregation of morphological types was found).
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- July 1989
- Bibcode:
- 1989A&A...218...49V
- Keywords:
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- Disk Galaxies;
- Galactic Structure;
- Hydrogen Atoms;
- Angular Velocity;
- Astronomical Maps;
- Continuous Radiation;
- Density Distribution;
- Galactic Rotation;
- Spatial Distribution;
- Astrophysics