Spectroscopic observations of three elliptical galaxies
1980; Oxford University Press; Volume: 193; Issue: 4 Linguagem: Inglês
10.1093/mnras/193.4.931
ISSN1365-2966
AutoresG. Efstathiou, Richard S. Ellis, D. Carter,
Tópico(s)Astronomy and Astrophysical Research
ResumoWe report on spectroscopic observations of three elliptical galaxies, NGC 4472, NGC 5813 and IC 4296. Rotation curves, velocity dispersion profiles and line-strength profiles have been obtained using two methods, the Fourier quotient method of Sargent et al. (1977) and the cross-correlation method of Tonry & Davis. Good agreement was found between these methods. NGC 4472 and 5813 are found to rotate slowly, providing additional support to the hypothesis that the shapes of elliptical galaxies are due to velocity anisotropics rather than rotation. IC 4296 rotates quite rapidly, consistent with isotropic oblate models. Spectra obtained along the minor axis of each galaxy show little evidence for minor axis rotation, except possibly for NGC 5813. The velocity dispersion profiles for NGC 5813 and IC 4296 are flat, implying a mass distribution |$\rho(r)\propto r^{-2}$|. Isophotometry has been obtained for each galaxy. NGC 4472 and 5813 show isophote twists and outwardly increasing ellipticities. Mass to light ratios have been determined for each galaxy and also for 10 galaxies in Schechter & Gunn's sample. We find |$(M/L)_\text B \sim 7$| in the inner regions (r ≈ 5kpc) of elliptical galaxies (assuming H0 = 50 km s−1 Mpc−1).
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