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On Density and Velocity Fields and β from the IRAS PSCz Survey

机译:IRAS PSCz调查中的密度和速度场以及β

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We present a version of the Fourier-Bessel method first introduced by Fisher and coworkers and Zaroubi and coworkers with two extensions: (1) we amend the formalism to allow a generic galaxy weight that can be constant, rather than the more conventional overweighting of galaxies at high distances, and (2) we correct for the masked zones by extrapolation of Fourier-Bessel modes rather than by cloning from the galaxy distribution in neighboring regions. We test the procedure extensively on N-body simulations and find that it gives generally unbiased results but that the reconstructed velocities tend to be overpredicted in high-density regions. Applying the formalism to the PSCz redshift catalog, we find that β = 0.7 ± 0.5 from a comparison of the reconstructed Local Group velocity to the cosmic microwave background dipole. From an anisotropy test of the velocity field, we find that β = 1 cold dark matter models normalized to the current cluster abundance can be excluded with 90% confidence. The density and velocity fields reconstructed agree with the fields found by Branchini and coworkers on most points. We find a back infall into the Great Attractor region (Hydra-Centaurus region), but tests suggest that this may be an artifact. We identify all the major clusters in our density field and confirm the existence of some previously identified possible ones.
机译:我们提出了由Fisher和他的同事以及Zaroubi和他的同事首先引入的傅里叶-贝塞尔方法的一种形式,它具有两个扩展:(1)我们修正形式主义,以使一般星系的重量可以恒定,而不是更常规的超重(2)我们通过傅里叶-贝塞尔模式的外推而不是通过克隆邻近区域的星系分布来校正掩盖区域。我们在N体模拟中对该程序进行了广泛的测试,发现该程序通常给出无偏结果,但是在高密度区域中,重构速度往往被过度预测。将形式主义应用于PSCz红移目录,我们从重构的局部群速度与宇宙微波背景偶极子的比较中发现,β= 0.7±0.5。从速度场的各向异性测试中,我们发现以90%的置信度可以排除对当前团簇丰度标准化的β= 1冷暗物质模型。重建的密度场和速度场与Branchini和同事在大多数点上发现的场一致。我们发现有一个巨大的吸引力区域(Hydra-Centaurus区域)倒退,但是测试表明这可能是人工产物。我们确定了密度场中的所有主要星团,并确认了一些先前确定的可能星团的存在。
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