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arXiv 1807.06381astro-ph.CO
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理解有偏示踪剂的重建

Understanding the Reconstruction of the Biased Tracer

Xin Wang, Ue-Li Pen

摘要:

近年来,在重建大尺度结构(LSS)方面取得了重大进展,至少从非线性物质场恢复线性重子声振荡(BAO)。这种优异的性能是通过迭代求解质量守恒的Monge-Ampere方程来实现的。然而,这种技术也依赖于几个假设是不成立的,在现实中,即纵向位移,壳交叉和均匀的初始条件的情况下,没有。特别地,示踪剂的守恒方程包括打破最后一个假设的偏置信息。因此,直接重建会使非线性位移与复杂的偏置参数纠缠在一起,进而影响BAO。在本文中,我们制定了一个理论模型,描述重建有偏映射匹配示踪剂的过密度与辅助流体与消失的初始扰动。关于重建算法的性能,我们表明,即使散粒噪声仍然是最重要的限制因素,在一个现实的调查,不适当的治疗的偏见也可能转移重建帧,因此扩大了BAO峰。我们建议,在原则上,这种偏见相关的BAO涂抹效果可以用来独立自校准的偏见参数。

英文摘要:

Recent development in the reconstruction of the large-scale structure (LSS) has seen significant improvement in restoring the linear baryonic acoustic oscillation (BAO) from at least the non-linear matter field. This outstanding performance is achieved by iteratively solving the Monge-Ampere equation of the mass conservation. However, this technique also relies on several assumptions that are not valid in reality, namely the longitudinal displacement, the absence of shell-crossing and homogeneous initial condition. In particular, the conservation equation of the tracers comprises the biasing information that breaks down the last assumption. Consequently, direct reconstruction would entangle the non-linear displacement with complicated bias parameters and further affect the BAO. In this paper, we formulate a theoretical model describing the reconstructed biased map by matching the tracer overdensity with an auxiliary fluid with vanishing initial perturbation. Regarding the performance of the reconstruction algorithm, we show that even though the shot noise is still the most significant limiting factors in a realistic survey, inappropriate treatment of the bias could also shift the reconstructed frame and therefore broaden the BAO peak. We suggest that, in principle, this bias-related BAO smearing effect could be used to independently self-calibrate the bias parameters.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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