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We revisit the well known discrepancy between the observed number of MilkyWay (MW) dwarf satellite companions and the predicted population of cold darkmatter (CDM) sub-halos, in light of the dozen new low luminosity satellitesfound in SDSS imaging data and our recent calibration of the SDSS satellitedetection efficiency, which implies a total population far larger than thesedozen discoveries. We combine a dynamical model for the CDM sub-halo populationwith simple, physically motivated prescriptions for assigning stellar contentto each sub-halo, then apply observational selection effects and compare to thecurrent observational census. As expected, models in which the stellar mass isa constant fraction F(Omega_b/Omega_m) of the sub-halo mass M_sat at the timeit becomes a satellite fail for any choice of F. However, previously advocatedmodels that invoke suppression of gas accretion after reionization in haloswith circular velocity v_c <~ 35 km/s can reproduce the observed satellitecounts for -15 < M_V < 0, with F ~ 10^{-3}. Successful models also requirestrong suppression of star formation BEFORE reionization in halos with v_c <~10 km/s; models without pre-reionization suppression predict far too manysatellites with -5 < M_V < 0. Our models also reproduce the observed stellarvelocity dispersions ~ 5-10 km/s of the SDSS dwarfs given the observed sizes oftheir stellar distributions, and model satellites have M(<300 pc) ~ 10^7 M_sunas observed even though their present day total halo masses span more than twoorders of magnitude. Our modeling shows that natural physical mechanisms actingwithin the CDM framework can quantitatively explain the properties of the MWsatellite population as it is presently known, thus providing a convincingsolution to the `missing satellite' problem.

A quantitative explanation of the observed population of Milky Way satellite galaxies