The Foundation Supernova Survey: Measuring Cosmological Parameters with Supernovae from a Single Telescope

Journal Article

Measurements of the dark energy equation-of-state parameter, $w$, have been limited by uncertainty in the selection effects and photometric calibration of $z<0.1$ Type Ia supernovae (SNe Ia). The Foundation Supernova Survey is designed to lower these uncertainties by creating a new sample of $z<0.1$ SNe Ia observed on the Pan-STARRS system. Here, we combine the Foundation sample with SNe from the Pan-STARRS Medium Deep Survey and measure cosmological parameters with 1,338 SNe from a single telescope and a single, well-calibrated photometric system. For the first time, both the low-$z$ and high-$z$ data are predominantly discovered by surveys that do not target pre-selected galaxies, reducing selection bias uncertainties. The $z>0.1$ data include 875 SNe without spectroscopic classifications and we show that we can robustly marginalize over CC SN contamination. We measure Foundation Hubble residuals to be fainter than the pre-existing low-$z$ Hubble residuals by $0.046 \pm 0.027$ mag (stat+sys). By combining the SN Ia data with cosmic microwave background constraints, we find $w=-0.938 \pm 0.053$, consistent with $\Lambda$CDM. With 463 spectroscopically classified SNe Ia alone, we measure $w=-0.933\pm0.061$. Using the more homogeneous and better-characterized Foundation sample gives a 55% reduction in the systematic uncertainty attributed to SN Ia sample selection biases. Although use of just a single photometric system at low and high redshift increases the impact of photometric calibration uncertainties in this analysis, previous low-$z$ samples may have correlated calibration uncertainties that were neglected in past studies. The full Foundation sample will observe up to 800 SNe to anchor the LSST and WFIRST Hubble diagrams.

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Duke Authors

Cited Authors

  • Jones, DO; Scolnic, DM; Foley, RJ; Rest, A; Kessler, R; Challis, PM; Chambers, KC; Coulter, DA; Dettman, KG; Foley, MM; Huber, ME; Jha, SW; Johnson, E; Kilpatrick, CD; Kirshner, RP; Manuel, J; Narayan, G; Pan, Y-C; Riess, AG; Schultz, ASB; Siebert, MR; Berger, E; Chornock, R; Flewelling, H; Magnier, EA; Smartt, SJ; Smith, KW; Wainscoat, RJ; Waters, C; Willman, M