High resolution reddening map in the direction of the stellar system
  Terzan 5
  We have used optical images acquired with the Hubble Space Telescope to
construct the first high-resolution extinction map in the direction of Terzan
5, a peculiar stellar system in the inner bulge of our Galaxy. The map has a
spatial resolution of 8" X 8", over a total FoV of 200" X 200". The absorption
clouds show a patchy structure on a typical scale of 20" and extinction
variations as large as delta E(B-V) = 0.67 mag, especially in the direction of
the center of the system. These correspond to an absolute color excess ranging
from E(B-V)=2.15 mag, up to 2.82 mag. After the correction for differential
reddening, two distinct red giant branches become clearly visible in the color
magnitude diagram of Terzan 5 and they well correspond to the two
sub-populations with different iron abundances recently discovered in this
system.
