Cosmological constraints from measurements of type Ia supernovae discovered during the first 1.5 yr of the Pan-STARRS1 survey
© 2014. The American Astronomical Society. All rights reserved. We present griz P1 light curves of 146 spectroscopically confirmed Type Ia supernovae (SNe Ia; 0.03 < z < 0.65) discovered during the first 1.5 yr of the Pan-STARRS1 Medium Deep Survey. The Pan-STARRS1 natural photometric system is determined by a combination of on-site measurements of the instrument response function and observations of spectrophotometric standard stars. We find that the systematic uncertainties in the photometric system are currently 1.2% without accounting for the uncertainty in the Hubble Space Telescope Calspec definition of the AB system. A Hubble diagram is constructed with a subset of 113 out of 146 SNe Ia that pass our light curve quality cuts. The cosmological fit to 310 SNe Ia (113 PS1 SNe Ia + 222 light curves from 197 low-z SNe Ia), using only supernovae (SNe) and assuming a constant dark energy equation of state and flatness, yields w = -1.120 +0.360-0.206 (Stat) +0.2690.291 (Sys). When combined with BAO+CMB(Planck)+H 0 , the analysis yields Ω M = 0.280 +0.0130.012 and w = -1.166 +0.072-0.069 including all identified systematics. The value of w is inconsistent with the cosmological constant value of -1 at the 2.3σ level. Tension endures after removing either the baryon acoustic oscillation (BAO) or the H 0 constraint, though it is strongest when including the H 0 constraint. If we include WMAP9 cosmic microwave background (CMB) constraints instead of those from Planck, we find w = -1.124 +0.083-0.065 , which diminishes the discord to <2σ. We cannot conclude whether the tension with flat ΛCDM is a feature of dark energy, new physics, or a combination of chance and systematic errors. The full Pan-STARRS1 SN sample with ∼three times as many SNe should provide more conclusive results.
Rest, A; Scolnic, D; Foley, RJ; Huber, ME; Chornock, R; Narayan, G; Tonry, JL; Berger, E; Soderberg, AM; Stubbs, CW; Riess, A; Kirshner, RP; Smartt, SJ; Schlafly, E; Rodney, S; Botticella, MT; Brout, D; Challis, P; Czekala, I; Drout, M; Hudson, MJ; Kotak, R; Leibler, C; Lunnan, R; Marion, GH; McCrum, M; Milisavljevic, D; Pastorello, A; Sanders, NE; Smith, K; Stafford, E; Thilker, D; Valenti, S; Wood-Vasey, WM; Zheng, Z; Burgett, WS; Chambers, KC; Denneau, L; Draper, PW; Flewelling, H; Hodapp, KW; Kaiser, N; Kudritzki, RP; Magnier, EA; Metcalfe, N; Price, PA; Sweeney, W; Wainscoat, R; Waters, C
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