期刊
ASTRONOMY & ASTROPHYSICS
卷 458, 期 1, 页码 79-88出版社
EDP SCIENCES S A
DOI: 10.1051/0004-6361:20065017
关键词
galaxy : kinematics and dynamics; galaxies : elliptical and lenticular cD; galaxies : structure; dark matter; galaxies : individual : NGC 1399; Galaxy : star clusters
Context. Of the various observational methods used to address the question of dark matter in early-type galaxies there is the possibility of spatial overlap in using kinematics of stars, clusters and X-ray halos. Aims. To investigate methods for the determination of velocity distribution profiles and deviations from a Gaussian distribution using globular clusters in early-type galaxies, and the implications for dark matter. Methods. The maximum likelihood method together with standard statistical procedures were used to calculate the velocity dispersion. A new tracer mass estimator was applied to obtain a mass estimate based on the globular clusters, which is then compared to the mass obtained using X-rays. Results. In NGC 1399 the departures from a Gaussian distribution of the velocities at all radial distances are small. Our conclusion is that in spite of the observations that show that the velocity dispersion decreases between 4 and 10 R-e there is evidence that dark matter exists beyond similar to 3 R-e.
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