The WiggleZ Dark Energy Survey: joint measurements of the expansion and growth history at z 1
Blake, Chris, Brough, Sarah, Colless, Matthew, Contreras, Carlos, Couch, Warrick, Croom, Scott, Croton, Darren, Davis, Tamara M., Drinkwater, Michael J., Forster, Karl, Gilbank, David, Gladders, Mike, Glazebrook, Karl, Jelliffe, Ben, Jurek, Russell J., Li, I-hui, Madore, Barry, Martin, D. Christopher, Pimbblet, Kevin, Poole, Gregory B., Pracy, Michael, Sharp, Rob, Wisnioski, Emily, Woods, David, Wyder, Ted K., Yee, H. K. C.
Abstract
We perform a joint determination of the distance–redshift relation and cosmic expansion rate at redshifts z = 0.44, 0.6 and 0.73 by combining measurements of the baryon acoustic peak and Alcock–Paczynski distortion from galaxy clustering in the WiggleZ Dark Energy Survey, using a large ensemble of mock catalogues to calculate the covariance between the measurements. We find that DA(z) = (1205 ± 114, 1380 ± 95, 1534 ± 107) Mpc and H(z) = (82.6 ± 7.8, 87.9 ± 6.1, 97.3 ± 7.0) km s−1 Mpc−1 at these three redshifts. Further combining our results with other baryon acoustic oscillation and distant supernovae data sets, we use a Monte Carlo Markov Chain technique to determine the evolution of the Hubble parameter H(z) as a stepwise function in nine redshift bins of width & 0916;z = 0.1, also marginalizing over the spatial curvature. Our measurements of H(z), which have precision better than 7 per cent in most redshift bins, are consistent with the expansion history predicted by a cosmological constant dark energy model, in which the expansion rate accelerates at redshift z < 0.7.