Corresponding best-fit SFH models of the Warhol arc that generate the SED and B/R ratio shown in Fig. 7 with the band representing the 1σ tolerance from MCMC analysis. One can see that the inclusion of the B/R ratio as a constraint on top of the SED gives rise to a different SFH, with more star formation over the past 10 − 50 Myr (factor of ∼60 with ≳3σ significance) and less star formation over the last 50 − 250 Myr (factor of ∼60 with 2σ).