Biased tracers of two fluids in the Lagrangian picture
Biased tracers of two fluids in the Lagrangian picture
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DOI：
10.1088/1475-7516/2019/06/006
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发表时间：
2019-03
影响因子：
6.4
通讯作者：
Shi-Fan Chen;E. Castorina;M. White
中科院分区：
文献类型：
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作者：
Shi-Fan Chen;E. Castorina;M. White
我们探讨拉格朗日微扰理论（LPT）的存在下，有偏见的示踪剂在两种流体，专注于冷暗物质（CDM）和重子的情况下。两种流体的存在下诱导修正拉格朗日偏置膨胀和示踪剂平流，这两个我们制定的拉格朗日运动方程的三个线性模式的扩展。我们计算的线性阶两种流体的Zeldovich近似的修正，发现修改的偏差膨胀和示踪剂平流都进入在一个大范围的波数在低红移和绘制平行的欧拉形式主义的水平校正。然后，我们讨论了非线性校正的两种流体的图片，并计算贡献的相对速度效应（Δ vr2）在一个循环的顺序。最后，我们进行了探索性Fisher分析，以评估双流体校正对重子声振荡（BAO）测量的影响，发现虽然相对偏差参数的适度值可以在测量的BAO标度中引入高达0.5 σ的系统偏差，但将这些效应拟合为额外的参数，在很宽的偏差值范围内将误差条增加不到30%。
We explore Lagrangian perturbation theory (LPT) for biased tracers in the presence of two fluids, focusing on the case of cold dark matter (CDM) and baryons. The presence of two fluids induces corrections to the Lagrangian bias expansion and tracer advection, both of which we formulate as expansions in the three linear modes of the Lagrangian equations of motion. We compute the linear-order two-fluid corrections in the Zeldovich approximation, finding that modifications to the bias expansion and tracer advection both enter as percent-level corrections over a large range of wavenumbers at low redshift and draw parallels with the Eulerian formalism. We then discuss nonlinear corrections in the two-fluid picture, and calculate contributions from the relative velocity effect (∝ vr2) at one loop order. Finally, we conduct an exploratory Fisher analysis to assess the impact of two-fluid corrections on baryon acoustic oscillations (BAO) measurements, finding that while modest values of the relative bias parameters can introduce systematic biases in the measured BAO scale of up to 0.5 σ, fitting for these effects as additional parameters increases the error bar by less than 30% across a wide range of bias values.