TITLE:
Weak lensing and CMB: parameter forecasts including a running spectral index.
AUTHOR(S):
Mustapha Ishak,
Christopher M. Hirata,
Patrick McDonald, and
Uros Seljak (Princeton University)
DATE:
2003 Aug 25 (arXiv, v1, posted);
2003 Aug 25 (Phys. Rev. D, submitted);
2003 Dec 23 (revised);
2004 Jan 07 (Phys. Rev. D, accepted);
2004 Jan 15 (arXiv, v2, posted);
2004 Apr 20 (Phys. Rev. D, published).
AVAILABILITY:
arXiv
astro-ph/0308446 (free); APS (requires subscription).
PUBLICATION INFORMATION: Physical Review D, 69, 083514 (2004), 11 pages.
ABSTRACT:
We use statistical inference theory to explore the constraints from future galaxy weak lensing (cosmic shear) surveys combined with the
current CMB constraints on cosmological parameters, focusing particularly on the running of the spectral index of the primordial scalar
power spectrum, as. Recent papers have drawn attention to the possibility of measuring as
by combining the CMB with
galaxy clustering and/or the Lyman-a forest. Weak lensing combined with the CMB provides an alternative probe
of the primordial
power spectrum. We run a series of simulations with variable runnings and compare them to semi-analytic non-linear mappings to test
their validity for our calculations. We find that a "Reference" cosmic shear survey with fsky=0.01 and
6.6x108 galaxies
per steradian can reduce the uncertainty on ns
and as
by roughly a factor of 2 relative to the CMB alone. We investigate the
effect of shear calibration biases on lensing by including the calibration factor as a parameter, and show that for our Reference
Survey, the precision of cosmological parameter determination is only slightly degraded even if the amplitude calibration is uncertain
by as much as 5%. We conclude that in the near furure, weak lensing surveys can supplement the CMB observations to constrain the
primordial power spectrum, though not at the expected precision of combined CMB + Lyman-a forest analysis.
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