VISTA ZJKs photometry of Sgr dSph

We list locations and ZJKs-band magnitudes for over 2.9 million sources in the field. We discuss the isolation of the Sgr dSph from the foreground and Galactic Bulge populations, identify the Sgr dSph's horizontal branch in the near-infrared for the first time and map the density of the galaxy's stars.

We present isochrones for the Sgr dSph and Bulge populations. These are consistent with the previously reported properties of the Sgr dSph core: namely that it is dominated by a population between [Fe/H]~-1dex and solar, with a significant [{alpha}/Fe] versus [Fe/H] gradient. While strong contamination from the Galactic Bulge prevents accurate measurement of the (Galactic) north side of the Sgr dSph, the dwarf galaxy can be well approximated by a roughly ovaloid projection of characteristic size 4{deg}x2{deg}, beyond which the projected stellar density is less than half that of the region surrounding the core.