  There has recently been interest in multi-Solar mass Primordial Black Holes
(PBHs) as a dark matter (DM) candidate. There are various microlensing,
dynamical and accretion constraints on the abundance of PBHs in this mass
range. Taken at face value these constraints exclude multi-Solar mass PBHs
making up all of the DM for both delta-function and extended mass functions.
However the stellar microlensing event rate depends on the density and velocity
distribution of the compact objects along the line of sight to the Magellanic
Clouds. We study the dependence of the constraints on the local dark matter
density and circular speed and also consider models where the velocity
distribution varies with radius. We find that the largest mass constrained by
stellar microlensing can vary by an order of magnitude. In particular the
constraints are significantly weakened if the velocity dispersion of the
compact objects is reduced. The change is not sufficiently large to remove the
tension between the stellar microlensing and dynamical constraints. However
this demonstrates that it is crucial to take into account astrophysical
uncertainties when calculating and comparing constraints. We also confirm the
recent finding that the tension between the constraints is in fact increased
for realistic, finite width mass functions.
