The extensive age gradient of the Carina dwarf galaxy
  The evolution of small systems such as dwarf spheroidal galaxies (dSph) is
likely to have been a balance between external environmental effects and
internal processes within their own relatively shallow potential wells.
Assessing how strong such environmental interactions may have been is therefore
an important element in understanding the baryonic evolution of dSphs and their
derived dark matter distribution.
  Here we present results from a wide-area CTIO/MOSAIC II photometric survey of
the Carina dSph, reaching down to about two magnitudes below the oldest main
sequence turn-off (MSTO). This data-set enables us to trace the structure of
Carina in detail out to very large distances from its center, and as a function
of stellar age.
  We observe the presence of an extended structure made up primarily of ancient
MSTO stars, at distances between 25arcmin-60arcmin from Carina's center,
confirming results in the literature that Carina extends well beyond its
nominal tidal radius.
  The large number statistics of our survey reveals features such as isophote
twists and tails that had gone undetected in other previous shallower surveys.
This is the first time that such unambiguous signs of tidal disruption have
been found in a Milky Way "classical" dwarf other than Sagittarius.
  We also demonstrate the presence of a negative age gradient in Carina
directly from its MSTOs, and trace it out to very large distances from the
galaxy center. The signs of interaction with the Milky Way make it unclear
whether the age gradient was already in place before Carina underwent tidal
disruption.
