http://arxiv.org/abs/1407.5453
We forecast future constraints on local-type primordial non-Gaussianity parameter $f_{\rm NL}$ with a photometric galaxy survey by Euclid, a continuum galaxy survey by Square Kilometre Array (SKA), and their combination. We derive a general expression for the covariance matrix of the power spectrum estimates of multiple tracers to show how the so-called multi-tracer technique improves constraints on $f_{\rm NL}$. In particular we clarify the role of the overlap fraction of multiple tracers and the division method of the tracers. Our Fisher matrix analysis indicates that stringent constraints of $\sigma (f_{\rm NL})\lesssim 1$ can be obtained even with a single survey, assuming $5$ mass bins. When Euclid and SKA phase 1 (2) are combined, constraints on $f_{\rm NL}$ are improved to $\sigma (f_{\rm NL})= 0.34~(0.31)$.
D. Yamauchi, K. Takahashi and M. Oguri
Tue, 22 Jul 14
39/45
Comments: 5 pages, 4 figures
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