Observed SED of the 8 o’clock arc with the photometry of the lensed image A2 not corrected for gravitational lensing (blue points with error bars). Best-fit SED models obtained with templates with nebular emission (black line and red crosses showing the synthetic fluxes in the broad-band filters) and without nebular emission (magenta line). The dotted magenta lines show the contributions of a two-population fit, assuming a maximally old stellar population (~2.3   Gyr for an instantaneous burst), plus a younger stellar population with a variable age and star-formation history. The sum of the two (green dashed line) also provides a reasonable fit. Its stellar mass, however, significantly exceeds the dynamical mass.