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Galactic bulge microlensing surveys provide a probe of Galactic structure. Wepresent the first field-by-field comparison between microlensing observationsand the Besan\c{c}on population synthesis Galactic model. Using an updatedversion of the model we provide maps of optical depth, average event durationand event rate for resolved source populations and for difference imaging (DIA)events. We also compare the predicted event timescale distribution to thatobserved. The simulation follows the selection criteria of the MOA-II survey(Sumi et al. 2013). We modify the Besan\c{c}on model to include M dwarfs andbrown dwarfs. Our best fit model requires a brown dwarf mass function slope of$-0.4$. The model provides good agreement with the observed average duration,and respectable consistency with the shape of the timescale distribution(reduced $\chi^2 \simeq 2.2$). The DIA and resolved source limiting yieldsbracket the observed number of events by MOA-II ($2.17\times$ and $0.83\times$the number observed, respectively). We perform a 2-dimensional fit to the eventspatial distribution to predict the optical depth and event rate across theGalactic bulge. The most serious difficulty for the model is that it providesonly $\sim 50\%$ of the measured optical depth and event rate per star at lowGalactic latitude around the inner bulge ($|b|<3{^\circ}$). This discrepancymost likely is associated with known under-estimated extinction and star countsin the innermost regions and therefore provides additional support for amissing inner stellar population.

Besan\c{c}on Galactic model analysis of MOA-II microlensing: evidence for a mass deficit in the inner bulge