ar X iv : a st ro - p h / 02 11 41 1 v 1 1 8 N ov 2 00 2 2 dF Spectroscopy of M 104 Globular Clusters
نویسنده
چکیده
We present preliminary results of 2dF spectroscopy of globular clusters in The Sombrero (M104). We find 56 new clusters, and compile a total sample of 103 velocities combined with previous data. Our 2dF data extend out to 20 arcmin radius (∼50 kpc), much further than previous studies. In the combined sample, we tentatively find a steep drop in the velocity dispersion with radius, which might possibly indicate a truncated halo. There is no obvious solid-body rotation over all radii, but separate fits for those clusters inside and outside 25 kpc radius show tantalizing evidence for counter-rotation. The projected mass estimator with isotropic orbits yields an M104 mass of 1.2×10M⊙ inside 50 kpc, and a (M/L)B = 30: solid evidence for a dark matter halo in this galaxy.
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