When using closely-spaced medium-band observed filters, the template fluxes are found to be more robust than interpolating between observed filters (see Brammer et al. *in prep*). The resulting $U$-$V$ colors have average uncertainties of $\sim$0.058$\pm$0.008 mag for the entire sample of massive ($>$10$^{11}$M$_{\odot}$) galaxies, as determined from both systematic uncertainties and Monte Carlo simulations (described in detail in §3.2).

We fit the photometry with stellar population synthesis templates using FAST [@Kriek09], fixing the redshift to the EAZY output (or the spectroscopic redshift where available), and determine the best-fit age, dust extinction, star formation timescale, stellar mass, and star formation rate. The models input to FAST are a grid of @Maraston05 models that assume a @Kroupa01 IMF with solar metallicity and a range of ages (7.6-10.1 Gyrs), exponentially declining star formation histories ($7<\tau<10$ in log years) and dust extinction ($0<A_{V}<4$). The dust content is parameterized by the extinction in the V-band following the @Calzetti00 extinction law[^3].

![image](fig1_sm.eps)

In this paper, we select massive ($>$10$^{11}$M$_{\odot}$) galaxies in four redshift bins from the NMBS that sample roughly equal co-moving volumes (with the exception of the lowest redshift bin). Within this sample of massive galaxies, we are interested in understanding galaxies that are on 