http://arxiv.org/abs/1509.07585
With a radio continuum galaxy survey by Square Kilometre Array (SKA), a photometric galaxy survey by Euclid and their combination, we forecast future constraints on primordial non-Gaussianity. We focus on the potential impact of local-type higher-order nonlinear parameters on the parameter estimation and particularly the confirmation of the inflationary consistency inequality. Non-standard inflationary models, such as multi-field models, introduce the scale-dependent stochastic clustering of galaxies on large scales, which is a unique probe of mechanism for generating primordial density fluctuations. Our Fisher matrix analysis indicates that a deep and wide survey provided by SKA is more advantageous to constrain $\tau_{\rm NL}$, while Euclid has a strong constraining power for $f_{\rm NL}$ due to the redshift information, suggesting that the joint analysis between them are quite essential to break the degeneracy between $f_{\rm NL}$ and $\tau_{\rm NL}$. The combination of full SKA and Euclid will achieve the precision level needed to confirm the consistency inequality even for $f_{\rm NL}\approx 0.9$ and $\tau_{\rm NL}\approx 8$, though it is still hard for a single survey to confirm it when $f_{\rm NL}\lesssim 1.5$.
D. Yamauchi and K. Takahashi
Mon, 28 Sep 15
62/67
Comments: 5 pages, 2 figures
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