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Redshift Distortions and Omega in IRAS Surveys

A. J. S. Hamilton
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Abstract

Redshift space distortions on large scales can be used to measure the linear growth rate parameter $\ff \approx Ω^{0.6}/b$. I report here measurements of such distortions in the IRAS 2 Jy, 1.2 Jy, and QDOT redshift surveys, finding $\ff = 0.69^{+ .21}_{- .19}$ from a merged QDOT plus 1.2 Jy catalogue. Unfortunately, confidence in this result is undermined by a marked ($4σ$) change in the pattern of clustering in QDOT beyond about $80 h^{-1} Mpc$. A similar effect may be present at a mild level in the 1.2 Jy survey. The effect may be caused by systematic variation in the effective flux limit of the IRAS PSC over the sky, with a dispersion of $\sim 0.1$ Jy on scales $\sim 7^{\circ}$. If so, then the value of $\ff$ inferred from redshift distortions in IRAS surveys may be systematically underestimated.

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A. J. S. Hamilton. 1997-10-02. Redshift Distortions and Omega in IRAS Surveys. https://arxiv.org/abs/astro-ph/9507022

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