Discussion

• Summary of results
  • So far, fortunately, no strong evidence for IMF variations, but that doesn't mean for sure that they're not there

  • MW and M31 bulges differ. Disks contain stars of wide range of ages, with no clear strong burstiness.

  • Wide range of SFHs apparent in LG galaxies.
    • No strong evidence for extreme burstiness in star formation rates in majority of LG galaxies. Mild variations of SF rate likely.

    • Dwarfs away from large galaxies all have ongoing SF except Tucana, Antlia?, Cetus?

    • Dwarfs near to large galaxies don't have ongoing SF except LMC, SMC

    • SF not generally correlated with luminosity or mass (latter may be uncertain, however). Higher mass systems generally have ongoing SF, but not NGC 147, 185, 205

  • What is responsible for variety of SF histories?
    • Does variety of SFHs occur because SF is a stochastic process?

    • Does variety of SFHs occur because present-day properties of galaxies may not reflect past ones?

    • Does variety of SFHs reflect interaction epoch/orbital characteristics of a galaxy?

  • What are the processes that are most important for triggering star formation?
    • Seems plausible that bursting mode is related to interactions. But why not always?

    • Evidence for effect of ionizing background?

• LG stellar populations as a cosmological training sample
  • Challenges from the stellar populations perspective for the LCDM paradigm
    • The MW halo. Chemically cannot be assembled from present-day dwarfs.

    • Disks in LG appear to have stars of wide range of ages

    • Large fraction (all?) present galaxies appear to host ancient stars

    • Abundance-luminosity relation, spread, and observed abundance ratios

  • What are the best observational constraints for models?
    • Concentrate on quantities that are robust, i.e. the ``climate, not the local weather''
      • Relative numbers of stars in broad age bins as function of current galaxy luminosity, morphology, location

      • ``Burstiness-index'', e.g. what fraction of stars are formed in SF events that have SFR greater than some significant multiple of the mean SFR, but can only constrain in bins of $\sim$ log(age).

  • What do we need from models?
    • How important is stellar mixing within individual systems?

    • How are current day global properties related to past ones? Are LG dwarfs single primordial systems?

    • Models must attempt to consider chemical information

    • How representative is the Local Group from a cosmological perspective?

• The Future
  • Better, homogeneous, SF histories. Incorporation of external information: metallicities, metallicity distributions, abundance ratios

  • Better MW data, e.g. RAVE, GAIA, SIM, etc.

  • Main sequence turnoff photometry throughout the Local Group? Almost certainly for MW neighbors from ground-based photometry, but will need to be well motivated to do throughout the Local Group (a finite data set!); at least, HB photometry?

  • Proper motions and orbits of LG galaxies

  • SF histories from more distant galaxies: resolved bright stars and unresolved systems

• The End