Details

Autor(en) / Beteiligte

• Betoule, M.
• Kessler, R.
• Guy, J.
• Mosher, J.
• Hardin, D.
• Biswas, R.
• Astier, P.
• El-Hage, P.
• Konig, M.
• Kuhlmann, S.
• Marriner, J.
• Pain, R.
• Regnault, N.
• Balland, C.
• Bassett, B. A.
• Brown, P. J.
• Campbell, H.
• Carlberg, R. G.
• Cellier-Holzem, F.
• Cinabro, D.
• Conley, A.
• D’Andrea, C. B.
• DePoy, D. L.
• Doi, M.
• Ellis, R. S.
• Fabbro, S.
• Filippenko, A. V.
• Foley, R. J.
• Frieman, J. A.
• Fouchez, D.
• Galbany, L.
• Goobar, A.
• Gupta, R. R.
• Hill, G. J.
• Hlozek, R.
• Hogan, C. J.
• Hook, I. M.
• Howell, D. A.
• Jha, S. W.
• Le Guillou, L.
• Leloudas, G.
• Lidman, C.
• Marshall, J. L.
• Möller, A.
• Mourão, A. M.
• Neveu, J.
• Nichol, R.
• Olmstead, M. D.
• Palanque-Delabrouille, N.
• Perlmutter, S.
• Prieto, J. L.
• Pritchet, C. J.
• Richmond, M.
• Riess, A. G.
• Ruhlmann-Kleider, V.
• Sako, M.
• Schahmaneche, K.
• Schneider, D. P.
• Smith, M.
• Sollerman, J.
• Sullivan, M.
• Walton, N. A.
• Wheeler, C. J.

Titel

Improved cosmological constraints from a joint analysis of the SDSS-II and SNLS supernova samples

Ist Teil von

• Astronomy and astrophysics (Berlin), 2014-08, Vol.568, p.1-32

Ort / Verlag

United States: EDP Sciences

Erscheinungsjahr

2014

Link zum Volltext

Quelle

EZB Electronic Journals Library

Beschreibungen/Notizen

• Aims. We present cosmological constraints from a joint analysis of type Ia supernova (SN Ia) observations obtained by the SDSS-II and SNLS collaborations. The dataset includes several low-redshift samples (z< 0.1), all three seasons from the SDSS-II (0.05 <z< 0.4), and three years from SNLS (0.2 <z< 1), and it totals 740 spectroscopically confirmed type Ia supernovae with high-quality light curves. Methods. We followed the methods and assumptions of the SNLS three-year data analysis except for the following important improvements: 1) the addition of the full SDSS-II spectroscopically-confirmed SN Ia sample in both the training of the SALT2 light-curve model and in the Hubble diagram analysis (374 SNe); 2) intercalibration of the SNLS and SDSS surveys and reduced systematic uncertainties in the photometric calibration, performed blindly with respect to the cosmology analysis; and 3) a thorough investigation of systematic errors associated with the SALT2 modeling of SN Ia light curves. Results. We produce recalibrated SN Ia light curves and associated distances for the SDSS-II and SNLS samples. The large SDSS-II sample provides an effective, independent, low-z anchor for the Hubble diagram and reduces the systematic error from calibration systematics in the low-z SN sample. For a flat ΛCDM cosmology, we find Ωm =0.295 ± 0.034 (stat+sys), a value consistent with the most recent cosmic microwave background (CMB) measurement from the Planck and WMAP experiments. Our result is 1.8σ (stat+sys) different than the previously published result of SNLS three-year data. The change is due primarily to improvements in the SNLS photometric calibration. When combined with CMB constraints, we measure a constant dark-energy equation of state parameter w =−1.018 ± 0.057 (stat+sys) for a flat universe. Adding baryon acoustic oscillation distance measurements gives similar constraints: w =−1.027 ± 0.055. Our supernova measurements provide the most stringent constraints to date on the nature of dark energy.