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The Sagittarius galaxy (Sgr), the closest satellite galaxy of the Milky Way, has survived for many orbits about the Galaxy. Extant numerical calculations modeled this galaxy as a system with a centrally-concentrated mass profile, following the light, and found that it should lose more than one-half of its mass every 2--4 orbits and be completely disrupted long before now. Apparently Sgr, and by implication other dSph galaxies, do not have a centrally-concentrated profile for their dark matter. We develop a model in which the stars of the Sgr dwarf are embedded in a constant-density dark matter halo, representing the core of a tidally-limited system, and show that this is consistent with its survival. We present new photometric and kinematic observations of Sgr and show these data are consistent with this explanation for the continued existence of this galaxy. Sgr is being tidally distorted and is tidally limited, but is not disrupted as yet. The corresponding minimum total mass is 10⁹ \, while the central mass to visual light ratio \ 50 in Solar units. Our new photographic photometry allows the detection of main-sequence stars of Sgr over an area of 22\ \ 8\. Sgr is prolate, with axis ratios center on the opposite side of the Galaxy to the Sun, the major axis is \ 9 Galaxy, roughly following the coordinate line \=5^\. The central velocity dispersion of giant stars which are members of Sgr is 11. 4 \ 0. 7 \ and is consistent with being constant over the face of the galaxy. The gradient in mean line-of-sight velocity with position along the
Ibata et al. (Sat,) studied this question.