We present an in-depth study of surface brightness fluctuations ( SBFs ) in low-luminosity stellar systems .
Using the MIST models , we compute theoretical predictions for absolute SBF magnitudes in the LSST , HST , and proposed WFIRST filter systems .
We compare our calculations to the observed SBF magnitudes of dwarf galaxies that have independent distance measurements from the tip of the red giant branch method .
Consistent with previous studies , we find that single-age population models show excellent agreement with the observed SBF-color relation of low-mass galaxies with 0.5 \lesssim g - i \lesssim 0.9 .
For bluer galaxies , the observed relation is better fit by models with composite stellar populations .
To study SBF recovery from low-luminosity galaxies , we perform detailed image simulations in which we inject fully populated model galaxies into deep ground-based images from real observations .
We demonstrate that measurements of SBF magnitudes from these simulated data correspond to the theoretical values with negligible bias ( \lesssim 0.01 mag ) .
We then use the simulations to show that LSST will provide data of sufficient quality and depth to measure SBF distances with precisions of { \sim } 10 -20 % to ultra-faint \left ( \mathrm { 10 ^ { 4 } \leq M _ { \star } / M _ { \odot } \leq 10 ^ { 5 } } \right ) and low-mass classical ( \leq 10 ^ { 7 } M _ { \odot } ) dwarf galaxies out to { \sim } 4 Mpc and { \sim } 25 Mpc , respectively , within the first few years of its deep-wide-fast survey .
Many systematic uncertainties remain , including an irreducible “ sampling scatter ” in the SBFs of ultra-faint dwarfs due to their undersampled stellar mass functions .
We nonetheless conclude that SBFs in the new generation of wide-field imaging surveys have the potential to play a critical role in the efficient confirmation and characterization of dwarf galaxies in the nearby universe .