VVV survey microlensing: candidate events with source in the far disk
  The VVV microlensing search has recently surveyed the region of the Galactic
plane at b=0 within -10.00 < l < 10.44 deg. in the near-infrared (IR),
discovering hundreds of microlensing events. In this paper we explore the
microlensing events with background sources that might be located in the far
disk of the Galaxy, beyond the bulge. We discuss the possible configurations
for the microlensing lenses and sources located at different places within the
Galactic plane. Then we search for these events using the local red clump
centroids of the VVV near-IR color-magnitude diagrams. According to the
estimated distances and proper motions, N=20 events may have sources located in
the far disk. The candidates for far-disk sources show on average longer
timescales (tE= 49.3 +- 7.9 days) than the mean of the timescale distribution
for the bulge red clump sources (tE= 36.4 +- 1.1 days). We conclude that the
population of microlensing events in the region -10.00 < l < 10.44, -0.46 < b <
0.65 deg. contains a non-negligible number of events with candidate far-disk
sources (~ 11 %). Our results are relevant in view of the future microlensing
plans with the Roman Space Telescope (formerly WFIRST) in the near-IR.
