The WiggleZ Dark Energy Survey: Testing the cosmological model with baryon acoustic oscillations at z= 0.6

Chris Blake, Tamara Davis, Gregory Poole, David Parkinson, Sarah Brough, Matthew Colless, Carlos Contreras, Warrwick Couch, Scott Croom, Michael Drinkwater, Karl Forster, David Gilbank, Michael Gladders, Karl Glazebrook, Ben Jelliffe, Russell Jurek, I-hui Li, Barry Madore, Damien Martin, Kevin PimbbletMichael Pracy, Robert Sharp, Emily Wisnioski, David Woods, Ted Wyder, Howard Yee

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    Abstract

    We measure the imprint of baryon acoustic oscillations (BAOs) in the galaxy clustering pattern at the highest redshift achieved to date, z= 0.6, using the distribution of N= 132509 emission-line galaxies in the WiggleZ Dark Energy Survey. We quantify BAOs using three statistics: the galaxy correlation function, power spectrum and the band-filtered estimator introduced by Xu et al. The results are mutually consistent, corresponding to a 4.0 per cent measurement of the cosmic distance-redshift relation at z= 0.6 [in terms of the acoustic parameter A(z) introduced by Eisenstein et al., we find A(z= 0.6) = 0.452 A? 0.018]. Both BAOs and power spectrum shape information contribute towards these constraints. The statistical significance of the detection of the acoustic peak in the correlation function, relative to a wiggle-free model, is 3.2I?. The ratios of our distance measurements to those obtained using BAOs in the distribution of luminous red galaxies at redshifts z= 0.2 and 0.35 are consistent with a flat I? cold dark matter model that also provides a good fit to the pattern of observed fluctuations in the cosmic microwave background radiation. The addition of the current WiggleZ data results in a a??30 per cent improvement in the measurement accuracy of a constant equation of state, w, using BAO data alone. Based solely on geometric BAO distance ratios, accelerating expansion (w <-1/3) is required with a probability of 99.8 per cent, providing a consistency check of conclusions based on supernovae observations. Further improvements in cosmological constraints will result when the WiggleZ survey data set is complete. 
    Original languageEnglish
    Pages (from-to)2892-2909
    Number of pages18
    JournalMonthly Notices of the Royal Astronomical Society
    Volume415
    Issue number3
    DOIs
    Publication statusPublished - 2011

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