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The Supernova Legacy Survey: Measurement of Omega_M, Omega_Lambda and w from the First Year Data Set

P. Astier·J. Guy·N. Regnault·R. Pain·E. Aubourg·D. Balam·S. Basa·R. G. Carlberg·S. Fabbro·D. Fouchez·I. M. Hook·D. A. Howell·H. Lafoux·J. D. Neill·N. Palanque-Delabrouille·K. Perrett·C. J. Pritchet·J. Rich·M. Sullivan·R. Taillet·G. Aldering·P. Antilogus·V. Arsenijevic·C. Balland·S. Baumont·J. Bronder·H. Courtois·R. S. Ellis·M. Filiol·A. C. Goncalves·A. Goobar·D. Guide·D. Hardin·V. Lusset·C. Lidman·R. McMahon·M. Mouchet·A. Mourao·S. Perlmutter·P. Ripoche·C. Tao·N. Walton
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Abstract

We present distance measurements to 71 high redshift type Ia supernovae discovered during the first year of the 5-year Supernova Legacy Survey (SNLS). These events were detected and their multi-color light-curves measured using the MegaPrime/MegaCam instrument at the Canada-France-Hawaii Telescope (CFHT), by repeatedly imaging four one-square degree fields in four bands. Follow-up spectroscopy was performed at the VLT, Gemini and Keck telescopes to confirm the nature of the supernovae and to measure their redshift. With this data set, we have built a Hubble diagram extending to z=1, with all distance measurements involving at least two bands. Systematic uncertainties are evaluated making use of the multi-band photometry obtained at CFHT. Cosmological fits to this first year SNLS Hubble diagram give the following results : Omega_M = 0.263 +/- 0.042(stat) +/- 0.032(sys) for a flat LambdaCDM model; and w = -1.023 +/- 0.090(stat) +/- 0.054(sys) for a flat cosmology with constant equation of state w when combined with the constraint from the recent Sloan Digital Sky Survey measurement of baryon acoustic oscillations.

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P. Astier, J. Guy, N. Regnault, R. Pain, E. Aubourg, D. Balam, S. Basa, R. G. Carlberg, S. Fabbro, D. Fouchez, I. M. Hook, D. A. Howell, H. Lafoux, J. D. Neill, N. Palanque-Delabrouille, K. Perrett, C. J. Pritchet, J. Rich, M. Sullivan, R. Taillet, G. Aldering, P. Antilogus, V. Arsenijevic, C. Balland, S. Baumont, J. Bronder, H. Courtois, R. S. Ellis, M. Filiol, A. C. Goncalves, A. Goobar, D. Guide, D. Hardin, V. Lusset, C. Lidman, R. McMahon, M. Mouchet, A. Mourao, S. Perlmutter, P. Ripoche, C. Tao, N. Walton. 2005-10-14. The Supernova Legacy Survey: Measurement of Omega_M, Omega_Lambda and w from the First Year Data Set. https://doi.org/10.1051/0004-6361%3A20054185

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