Journal Article

The WiggleZ Dark Energy Survey: measuring the cosmic expansion history using the Alcock–Paczynski test and distant supernovae

Chris Blake, Karl Glazebrook, Tamara M. Davis, Sarah Brough, Matthew Colless, Carlos Contreras, Warrick Couch, Scott Croom, Michael J. Drinkwater, Karl Forster, David Gilbank, Mike Gladders, Ben Jelliffe, Russell J. Jurek, I-hui Li, Barry Madore, D. Christopher Martin, Kevin Pimbblet, Gregory B. Poole, Michael Pracy, Rob Sharp, Emily Wisnioski, David Woods, Ted K. Wyder and H. K. C. Yee

in Monthly Notices of the Royal Astronomical Society

Published on behalf of The Royal Astronomical Society

Volume 418, issue 3, pages 1725-1735
Published in print December 2011 | ISSN: 0035-8711
Published online December 2011 | e-ISSN: 1365-2966 | DOI: http://dx.doi.org/10.1111/j.1365-2966.2011.19606.x
The WiggleZ Dark Energy Survey: measuring the cosmic expansion history using the Alcock–Paczynski test and distant supernovae

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Astronomical observations suggest that today’s Universe is dominated by a dark energy of unknown physical origin. One of the most notable results obtained from many models is that dark energy should cause the expansion of the Universe to accelerate: but the expansion rate as a function of time has proved very difficult to measure directly. We present a new determination of the cosmic expansion history by combining distant supernovae observations with a geometrical analysis of large-scale galaxy clustering within the WiggleZ Dark Energy Survey, using the Alcock–Paczynski test to measure the distortion of standard spheres. Our result constitutes a robust and non-parametric measurement of the Hubble expansion rate as a function of time, which we measure with 10–15 per cent precision in four bins within the redshift range 0.1 < z < 0.9. We demonstrate, in a manner insensitive to the assumed cosmological model, that the cosmic expansion is accelerating. Furthermore, we find that this expansion history is consistent with a cosmological-constant dark energy.

Keywords: surveys; dark energy; distance scale

Journal Article.  8001 words.  Illustrated.

Subjects: Astronomy and Astrophysics

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