The age-metallicity relationship in the Small Magellanic Cloud periphery
  We present results from Washington CT1 photometry for eleven star fields
located in the western outskirts of the Small Magellanic Cloud (SMC), which
cover angular distances to its centre from 2 up to 13 degrees (~ 2.2 - 13.8
kpc). The colour- magnitude diagrams, cleaned from the unavoidable Milky Way
(MW) and background galaxy signatures, reveal that the most distant dominant
main sequence (MS) stellar populations from the SMC centre are located at an
angular distance of ~ 5.7 deg (6.1 kpc); no sign of farther clear SMC MS is
visible other than the residuals from the MW/background field contamination.
The derived ages and metallicities for the dominant stellar populations of the
western SMC periphery show a constant metallicity level ([Fe/H] = -1.0 dex) and
an approximately constant age value (~ 7-8 Gyr). Their age-metallicity
relationship (AMR) do not clearly differ from the most comprehensive AMRs
derived for almost the entire SMC main body. Finally, the range of ages of the
dominant stellar populations in the western SMC periphery confirms that the
major stellar mass formation activity at the very early galaxy epoch peaked ~
7-8 Gyr ago.
