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

  • M. Betoule
  • , R. Kessler
  • , J. Guy
  • , J. Mosher
  • , D. Hardin
  • , R. Biswas
  • , P. Astier
  • , P. El-Hage
  • , M. Konig
  • , S. Kuhlmann
  • , J. Marriner
  • , R. Pain
  • , N. Regnault
  • , C. Balland
  • , B. A. Bassett
  • , P. J. Brown
  • , H. Campbell
  • , R. G. Carlberg
  • , F. Cellier-Holzem
  • , D. Cinabro
  • A. Conley, C. B. D'Andrea, D. L. Depoy, M. Doi, R. S. Ellis, S. Fabbro, A. V. Filippenko, R. J. Foley, J. A. Frieman, D. Fouchez, L. Galbany, A. Goobar, R. R. Gupta, G. J. Hill, R. Hlozek, C. J. Hogan, I. M. Hook, D. A. Howell, S. W. Jha, L. Le Guillou, G. Leloudas, C. Lidman, J. L. Marshall, A. Möller, A. M. Mourão, J. Neveu, R. Nichol, M. D. Olmstead, N. Palanque-Delabrouille, S. Perlmutter, J. L. Prieto, C. J. Pritchet, M. Richmond, A. G. Riess, V. Ruhlmann-Kleider, M. Sako, K. Schahmaneche, D. P. Schneider, M. Smith, J. Sollerman, M. Sullivan, N. A. Walton, C. J. Wheeler
  • Universités Paris VI and VII
  • University of Chicago
  • University of Chicago
  • Ernest Orlando Lawrence Berkeley National Laboratory
  • University of Pennsylvania School of Arts and Sciences
  • Argonne National Laboratory
  • Fermi National Accelerator Laboratory
  • African Institute for Mathematical Sciences
  • South African Astronomical Observatory
  • University of Cape Town
  • Texas A&M University
  • Institute of Astronomy
  • University of Portsmouth
  • University of Toronto
  • Wayne State University
  • University of Colorado Boulder
  • University of Tokyo
  • Research Center for the Early Universe
  • California Institute of Technology
  • University of Victoria
  • University of California, Berkeley
  • University of Illinois at Urbana-Champaign
  • University of Illinois
  • Aix Marseille Université
  • University of São Paulo
  • University of Chile
  • Oskar Klein Centre
  • The University of Texas at Austin
  • Princeton University
  • University of Oxford
  • Osservatorio Astronomico di Roma
  • Las Cumbres Observatory Global Telescope Network, Inc
  • University of California
  • Rutgers University–New Brunswick
  • Niels Bohr Institutet
  • Australian Astronomical Observatory
  • Institut Pierre Simon Laplace, CNRS and CEA
  • Instituto Superior Técnico
  • University of Utah
  • Rochester Institute of Technology
  • Johns Hopkins University
  • Space Telescope Science Institute
  • Pennsylvania State University
  • University of Western Cape
  • University of Southampton

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1688 Citations (Scopus)

Résumé

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.

langue originaleAnglais
Numéro d'articleA22
journalAstronomy and Astrophysics
Volume568
Les DOIs
étatPublié - 1 janv. 2014
Modification externeOui

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