20.07.2013 Views

Large-Scale Structure of the Universe and Cosmological ...

Large-Scale Structure of the Universe and Cosmological ...

Large-Scale Structure of the Universe and Cosmological ...

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

Fig. 58. The bispectrum Q3 vs. θ for <strong>the</strong> PSCz catalog for triangles with<br />

0.2 ≤ k1 ≤ 0.4 h/Mpc <strong>and</strong> with two sides <strong>of</strong> ratio k2/k1 = 0.4 − 0.6 separated<br />

by angle θ. The solid curve shows Q3 in redshift space averaged over many 2LPT<br />

realizations <strong>of</strong> <strong>the</strong> ΛCDM model. Symbols show results from <strong>the</strong> PSCz survey for<br />

b<strong>and</strong>s in k1: filled triangles, k1 = 0.20–0.24h/Mpc; filled squares 0.24–0.28; filled circles<br />

0.28-0.32; open circles 0.32–0.36; <strong>and</strong> open squares 0.36–0.42. The dashed curve<br />

shows <strong>the</strong> 2LPT prediction for ΛCDM with <strong>the</strong> best-fit bias parameters 1/b = 1.20,<br />

b2/b 2 = −0.42. Taken from [211].<br />

QDOT were marginal, due to <strong>the</strong> very sparse sampling (one galaxy every six)<br />

Q3 was only shown to be <strong>of</strong> order unity without any discernible dependence<br />

on configuration. The results from 1.9Jy <strong>and</strong> 1.2Jy showed a systematic shape<br />

dependence similar to that predicted by gravitational instability.<br />

These results were considerably extended with <strong>the</strong> analysis <strong>of</strong> <strong>the</strong> PSCz bispectrum<br />

[211]. Figure 58 shows <strong>the</strong> PSCz reduced bispectrum Q3 as a function<br />

<strong>of</strong> <strong>the</strong> angle θ between k1 <strong>and</strong> k2 for triangles with k1/k2 ≈ 2 <strong>and</strong> different<br />

scales as described in <strong>the</strong> figure caption [211]. The configuration dependence<br />

predicted by gravitational instability [232,313] (solid lines for an unbiased distribution,<br />

predicted by 2LPT, see e.g. Fig. 48) is clearly seen in <strong>the</strong> data. This<br />

is also <strong>the</strong> case for all triangles, not just those shown in Fig. 58, see Fig. 1<br />

in [211].<br />

Implications <strong>of</strong> <strong>the</strong>se results for galaxy biasing <strong>and</strong> primordial non-Gaussianity<br />

are discussed in Sect. 8.3.5.<br />

given in [669].<br />

252

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!