Precision Measurement of The Most Distant Spectroscopically Confirmed Supernova Ia with the Hubble Space Telescope
Huang, X.; Wang, L.; Lidman, C.; Amanullah, R.; Rubin, D.; Aldering, G.; Barbary, K.; Burns, M. S.; Conley, A.; Fakhouri, H. K.; Fruchter, A. S.; Goldhaber, G.; Goobar, A.; Knop, R. A.; Kowalski, M.; Meyers, J.; Nordin, J.; Perlmutter, S.; Spadafora, A. L.; Suzuki, N.; Supernova Cosmology Project, The; Hsiao, E. Y.; Rykoff, E.; Connolly, N.; Deustua, S.; Fadeyev, V.; Gibbons, R. A.; Saunders, C.; Stanishev, V.
United States, Canada, Sweden, Chile, Germany, Australia, Portugal
Abstract
We report the discovery of a redshift 1.71 supernova in the GOODS-North field. The Hubble Space Telescope (HST) ACS spectrum has almost negligible contamination from the host or neighboring galaxies. Although the rest-frame-sampled range is too blue to include any Si II line, a principal component analysis allows us to confirm it as a Type Ia supernova with 92% confidence. A recent serendipitous archival HST WFC3 grism spectrum contributed a key element of the confirmation by giving a host-galaxy redshift of 1.713 ± 0.007. In addition to being the most distant SN Ia with spectroscopic confirmation, this is the most distant Ia with a precision color measurement. We present the ACS WFC and NICMOS 2 photometry and ACS and WFC3 spectroscopy. Our derived supernova distance is in agreement with the prediction of ΛCDM.
Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by AURA, Inc., under NASA contract NAS 5-26555, under programs GO-9583, GO-9727, GO-9728, GO-10339, and GO-11600.