http://arxiv.org/abs/astro-ph/0605278(adsbygoogle = window.adsbygoogle || []).push({});

Searching for modified gravity with baryon oscillations: from SDSS to WFMOS

Authors: Kazuhiro Yamamoto, Bruce A. Bassett, Robert C. Nichol, Yasushi Suto, Kazuhiro Yahata

Comments: 16 pages, submitted to PRD

We discuss how the baryon acoustic oscillation (BAO) signatures in galaxy power spectrum can distinguish the two different models to explain the cosmic acceleration, the modified gravity and the cosmological constant. For this purpose, we consider a model characterized by a parameter n, which corresponds to the Dvali-Gabadadze-Porrati (DGP) model if n=2 and reduces to a spatially-flat cosmological model with a cosmological constant for n=\infty. We find that the different expansion history of the modified gravity model systematically shift the peak positions of BAO. A preliminary analysis using the current SDSS LRG sample indicates that the original DGP model is disfavored unless the matter density parameter exceeds 0.3. The constraints will be strongly tightened with future spectroscopic samples of galaxies at high redshifts. WFMOS, in collaboration with other surveys such as Planck, will powerfully constrain modified gravity alternatives to dark energy as the explanation of cosmic acceleration.

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