Constraints on local primordial non-Gaussianity from large scale structure
Constraints on local primordial non-Gaussianity from large scale structure
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DOI：
10.1088/1475-7516/2008/08/031
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发表时间：
2008-05
影响因子：
6.4
通讯作者：
A. Slosar;C. Hirata;U. Seljak;S. Ho;N. Padmanabhan
中科院分区：
文献类型：
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作者：
A. Slosar;C. Hirata;U. Seljak;S. Ho;N. Padmanabhan
最近的工作表明，局部非高斯参数fNL引起尺度依赖性偏差，其幅度随着尺度而增长。在这里，我们首先重新推导这个结果的背景下的峰值分裂形式主义，并表明它只依赖于假设的普遍性的质量函数，假设晕偏差只取决于质量。然后，我们使用扩展的Press-Schechter形式主义认为，这一假设可能会被违反，规模依赖的偏见将取决于其他属性，如合并的历史晕。特别是，在最近的合并的限制，我们发现，该效果被抑制。接下来，我们将这些预测与大规模数据的概要结合使用，以限制fNL的值。当结合所有数据时，假设晕占据仅取决于晕质量，我们得到-29（-65）<fNL<+70（+93），置信度为95%（99.7%）。虽然我们使用了广泛的数据集，但我们的综合结果主要是来自SDSS光度类星体样本的信号。如果后者被建模为最近的合并，则限制减弱为-31（-96）<fNL<+70（+96）。这些限值与威尔金森各向异性探测器（WMAP）五年分析的最强电流限值相当，没有证据表明fNL中存在阳性信号。虽然该方法需要进行彻底的测试，对大规模的结构模拟与现实的类星体和星系形成模型，我们的研究结果表明，这是一个有竞争力的方法相对于宇宙微波背景，应该进一步追求观测和理论。
Recent work has shown that the local non-Gaussianity parameter fNL induces a scale dependent bias, whose amplitude is growing with scale. Here we first rederive this result within the context of the peak–background split formalism and show that it only depends on the assumption of universality of the mass function, assuming that the halo bias only depends on the mass. We then use the extended Press–Schechter formalism to argue that this assumption may be violated and that the scale dependent bias will depend on other properties, such as the merging history of halos. In particular, in the limit of recent mergers we find that the effect is suppressed. Next we use these predictions in conjunction with a compendium of large scale data to put a limit on the value of fNL. When combining all data assuming that the halo occupation depends only on the halo mass, we get a limit of −29 (−65)<fNL<+70 (+93) at 95% (99.7%) confidence. While we use a wide range of data sets, our combined result is dominated by the signal from the SDSS photometric quasar sample. If the latter are modeled as recent mergers then the limits weaken to −31 (−96)<fNL<+70 (+96). These limits are comparable to the strongest current limits from the Wilkinson Anisotropy Probe (WMAP) five-year analysis, with no evidence of a positive signal in fNL. While the method needs to be thoroughly tested against large scale structure simulations with realistic quasar and galaxy formation models, our results indicate that this is a competitive method relative to the cosmic microwave background one and should be further pursued both observationally and theoretically.