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[26.04] LSST Supernovae and Cosmic Shear As Complementary Probes of Dark Energy

A. Albrecht, H. Zhan, L. Knox (UC Davis), Y.-S. Song (U. Chicago), J.A. Tyson, D. Wittman (UC Davis)

Weak lensing observations and supernova observations, combined with CMB observations, can both provide powerful constraints on dark energy properties. We find luminosity distances inferred from 2000 supernovae and large-scale (\ell < 1000) angular power spectra inferred from redshift-binned cosmic shear maps of half of the sky place complementary constraints on w₀ and w_{\rm a} where w(z) = w₀ + w_{\rm a} (a-1). Further, each set of observations can constrain higher-dimensional parameterizations of w(z) and constrains these in different ways. To quantify these abilities we consider eigenmodes of the w(z) error covariance matrix. The best-determined mode for each dataset has a standard deviation of about 0.03. This error rises quite slowly with increasing eigenmode number for the lensing data, reaching one only by the 7th mode. The eigenmode shapes also have interesting differences indicating that lensing is better at probing higher z while supernovae have their chief advantage at lower z. If the prior of a flat geometry is relaxed, the weak lens derived constraints on dark energy are much less affected than the SN constraints.

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Bulletin of the American Astronomical Society, 37 #4
© 2005. The American Astronomical Soceity.