HST (WFC3) image of M83 shown in greyscale. The positions of the HST/COS observed YSCs are overplotted as circles. The color fill of the circles represents the UV-spectrum-fitted average age (in Myr) of the younger stellar population. The coordinates (R.A., decl.) are given in J2000 format. Note that the circle sizes do not represent the HST/COS aperture, which is too small for clear representation in this figure. All YSCs are labeled with numbers, “X,” “OX,” and “(RX),” representing YSCs with IDs: “M83-X,” “M83-POS-X,” and “R(X),” respectively (see Table 2). The galactic center is highlighted with a magenta rectangle in the main figure, and a zoomed-in subfigure in the top-left corner shows the labels for the five clusters within the galactic center. The subfigure has a different flux normalization than the main image for clarity. The stellar ages shown here are values obtained from SB 99 models. For related stellar age uncertainty, please see Table 3.