Estimates for the impact of ultraviolet background fluctuations on galaxy clustering measurements
Estimates for the impact of ultraviolet background fluctuations on galaxy clustering measurements
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DOI：
10.1093/mnras/stz741
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发表时间：
2018-10
影响因子：
4.8
通讯作者：
Phoebe Upton Sanderbeck-Phoebe-Upton Sanderbeck-2124287587;V. Iršič;M. McQuinn;A. Meiksin
中科院分区：
文献类型：
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作者：
Phoebe Upton Sanderbeck-Phoebe-Upton Sanderbeck-2124287587;V. Iršič;M. McQuinn;A. Meiksin
紫外线背景的空间波动可以微妙地调节河外源的分布，这是一个潜在的信号，也是大规模结构调查的一个系统。虽然这种调制已经被证明对3D Ly α森林调查是重要的，但它与其他大尺度结构探测的相关性几乎没有被探索，尽管这是唯一可能影响100 Mpc尺度上的聚类测量的天体物理过程。我们估计，背景涨落，调制H i的量，对z = 1-3的21 cm强度图的功率谱有（0.03-0.3）×（k/[10−2 Mpc−1]）−1的分数效应。我们发现，对于H α和Ly α强度映射调查（0.001-0.1）×（k/[10−2 Mpc−1]）−1，影响较小，对于关联单个H α或Ly α发射体位置的更传统的调查，影响甚至更小。我们还估计了背景对低红移星系巡天的影响，这是基于一个简单的模型，在这个模型中，背景波动调节了晕气体冷却的速率，从而调节了星星的形成：我们估计了在z = 1时，背景对<$0.01（k/[10−2 Mpc−1]）−1的幂的最大分数效应。我们将这些印记的大小与下一代红移调查的宇宙学参数基准进行比较：我们发现，电离背景可能导致压缩三角形非高斯参数fNL的偏差，该偏差可能大于SPHEREx类星系调查的功率谱测量的单位，以及强度偏差的典型值。在k− 1 PL形式的形状上边缘化，其中PL是线性物质的功率谱，以更大的统计误差为代价消除了大部分这种偏差。
Spatial fluctuations in ultraviolet backgrounds can subtly modulate the distribution of extragalactic sources, a potential signal and systematic for large-scale structure surveys. While this modulation has been shown to be significant for 3D Ly α forest surveys, its relevance for other large-scale structure probes has been hardly explored, despite being the only astrophysical process that likely can affect clustering measurements on the scales of ≳Mpc. We estimate that the background fluctuations, modulating the amount of H i, have a fractional effect of (0.03–0.3) × (k/[10−2 Mpc−1])−1 on the power spectrum of 21 cm intensity maps at z = 1–3. We find a smaller effect for H α and Ly α intensity mapping surveys of (0.001–0.1) × (k/[10−2 Mpc−1])−1 and even smaller effect for more traditional surveys that correlate the positions of individual H α or Ly α emitters. We also estimate the effect of backgrounds on low-redshift galaxy surveys in general based on a simple model in which background fluctuations modulate the rate halo gas cools, modulating star formation: We estimate a maximum fractional effect on the power of ∼0.01 (k/[10−2 Mpc−1])−1 at z = 1. We compare sizes of these imprints to cosmological parameter benchmarks for the next generation of redshift surveys: We find that ionizing backgrounds could result in a bias on the squeezed triangle non-Gaussianity parameter fNL that can be larger than unity for power spectrum measurements with a SPHEREx-like galaxy survey, and typical values of intensity bias. Marginalizing over a shape of the form k−1PL, where PL is the linear matter power spectrum, removes much of this bias at the cost of ${\approx } 40{{\ \rm per\ cent}}$ larger statistical errors.