Velocity mapping and models of the elliptical galaxies NGC 720, NGC 1052, and NGC 4697
- Steward Observatory, Tucson, AZ (USA) Oxford Univ. (England) National Optical Astronomy Observatories, Tucson, AZ (USA) California Univ., Santa Cruz (USA)
CCD surface photometry and extensive long-slit spectroscopy are used to construct detailed models of the flattened ellipticals NGC 720, 1052, and 4697. The models are combined with the Jeans equations to yield predicted fields of line-of-sight velocity dispersion and streaming velocity. By comparing these fields with observed velocities, it is concluded that none of these systems can have isotropic velocity dispersion tensors, and diminishing the assumed inclination of any given galaxy tends to decrease the line-of-sight velocity dispersion and, counterintuitively, to increase the line-of-sight rotation speeds. The ratio of the line-of-sight velocity dispersion along the minor axis to that along the major axis is found to be a sensitive diagnostic of the importance of a third integral for the galaxy's structure. 48 refs.
- OSTI ID:
- 6149718
- Journal Information:
- Astrophysical Journal; (USA), Vol. 361; ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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