between the two methods are negligible, and the Lorentzian profiles have the advantage of require no additional assumptions. Most importantly, for spectra dominated by young stars, at S/N values typical of our spectra, population synthesis models may not provide a unique solution. There are also very large variations in the population synthesis models for young ages, with large uncertainties in how the Wolfe-Rayet phase, stellar winds, rotation, and other parameters are treated. Since mass loss and mixing processes in stellar evolution are still poorly understood, stellar phases, like Wolf-Rayet stars or Red Super Giants, are particularly affected by such uncertainties [@leitherer2011]. Later phases, like AGB stars, are covered only crudely in models or not at all, pushing parameters into regimes that are not properly calibrated. When discrepancies between models are found, they can usually be attributed to different intrinsic input parameters and/or treatment of these aberrant stellar evolutionary phases [@vazquez2005; @conroy2010]. By not using the models to fit our continuum, we avoid the uncertainties associated with these implicit assumptions.

The errors of the flux measurements were approximated using $$\sigma_{\lambda} \approx \sqrt{ {(2\times \sqrt{N}\times rms)}^2 + {(0.02\times F_{\lambda})}^2 } , \label{eq:uncertainty}$$ where N is the number of pixels spanning the Gaussian 