Program: GS-2015B-Q-8

A new era of supernova cosmology has begun, requiring new techniques and probes to both reduce the systematic uncertainties and extend the redshift range into the deceleration phase of the expansion history of the Universe. The Dark Energy Survey (DES) offers such an opportunity by discovering thousands of supernovae across a wide range of redshifts with excellent multi-wavelength light-curves. To take advantage of our recent agreement between Chilean SN astronomers and DES, we propose a three-fold spectroscopic strategy to fully exploit DES and develop new and exciting SN probes: a) the acquisition of a unique sample of type II supernova spectra at 0.05<z<0.6 to build the first cosmologically significant SN II Hubble diagram, b) the construction of the first cosmological measurement with superluminous SNe up to z~4, and c) the assembly of a homogeneous sample of SNe Ia from low-mass galaxies up to z ~ 1.0 to make a Hubble diagram exclusively from a single population of star-forming host galaxies, which have been shown to provide better standard candles than the entire SN Ia population. These studies will test cosmological models to unprecedented reach and accuracy, and build on the heritage of Chilean SN astronomers.