CLUES to the past: Local Group progenitors amongst high-redshift Lyman
  Break Galaxies
  We use state-of-the-art numerical simulations to explore the observability
and the expected physical properties of the progenitors of the local group
galaxies at z=6-8, within 1 billion years of the big bang. We find that the
most massive progenitors of the Milky Way (MW) and Andromeda (M31) at z=6 and 7
are predicted to have absolute UV continuum magnitudes between -17 and -18,
suggesting that their analogues lie close to the detection limits of the
deepest near-infrared surveys conducted to date (i.e. HST WFC3/IR UDF12). This
in turn confirms that the majority of currently known z=6-8 galaxies are
expected to be the seeds of present-day galaxies which are more massive than L*
spirals. We also discuss the properties of the local-group progenitors at these
early epochs, extending down to absolute magnitudes M_UV = -13. The most
massive MW/M31 progenitors at z=7 have stellar masses of about 10^7.5-8 solar
masses, stellar metallicities between 3 and 6% of the solar value, and
predicted observed UV continuum slopes between -2.4 and -2.5.
