Resolved and Integrated Stellar Masses in the SDSS-IV/MaNGA Survey. I. PCA Spectral Fitting and Stellar Mass-to-light Ratio Estimates

We present a method of fitting optical spectra of galaxies using a basis set of six vectors obtained from principal-component analysis of a library of synthetic spectra of 40,000 star formation histories (SFHs). Using this library, we provide estimates of the resolved effective stellar mass-to-light ratio ({{{\Upsilon }}}^* ) for thousands of galaxies from the SDSS-IV/MaNGA integral-field spectroscopic survey. Using a testing framework built on additional synthetic SFHs, we show that the estimates of {log}{{{\Upsilon }}}_i^* are reliable (as are their uncertainties) at a variety of signal-to-noise ratios, stellar metallicities, and dust attenuation conditions. Finally, we describe the future release of the resolved stellar mass-to-light ratios as an SDSS-IV/MaNGA Value-Added Catalog and provide a link to the software used to conduct this analysis. (The software can be found at https://github.com/zpace/pcay.)