Re-Assembling the Sagittarius Dwarf Galaxy
  What is the mass of the progenitor of the Sagittarius (Sgr) dwarf galaxy?
Here, we reassemble the stellar debris using SDSS and 2MASS data to find the
total luminosity and likely mass. We find that the luminosity is in the range
9.6-13.2 x10^7 solar luminosities or M_V ~ -15.1 - 15.5, with 70% of the light
residing in the debris streams. The progenitor is somewhat fainter than the
present-day Small Magellanic Cloud, and comparable in brightness to the M31
dwarf spheroidals NGC 147 and NGC 185. Using cosmologically motivated models,
we estimate that the mass of Sgr's dark matter halo prior to tidal disruption
was ~10^10 solar masses.
