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Cosmological simulation in tides: power spectra, halo shape responses, and shape assembly bias
Journal of Cosmology and Astroparticle Physics ( IF 6.4 ) Pub Date : 2021-04-16 , DOI: 10.1088/1475-7516/2021/04/041
Kazuyuki Akitsu , Yin Li , Teppei Okumura

The well-developed separate universe technique enables accurate calibration of the response of any observable to an isotropic long-wavelength density fluctuation. The large-scale environment also hosts tidal modes that perturb all observables anisotropically. As in the separate universe, both the long tidal and density modes can be absorbed by an effective anisotropic background, on which the interaction and evolution of the short modes change accordingly. We further develop the tidal simulation method, including proper corrections to the second order Lagrangian perturbation theory (2LPT) to generate initial conditions of the simulations. We measure the linear tidal responses of the matter power spectrum, at high redshift from our modified 2LPT, and at low redshift from the tidal simulations. Our results agree qualitatively with previous works, but exhibit quantitative differences in both cases. We also measure the linear tidal response of the halo shapes, or the shape bias, and find its universal relation with the linear halo bias, for which we provide a fitting formula. Furthermore, analogous to the assembly bias, we study the secondary dependence of the shape bias, and discover for the first time the dependence on the halo concentration and axis ratio. Our results provide useful insights for studies of the intrinsic alignment as a source of either contamination or information. These effects need to be correctly taken into account when one uses intrinsic alignments of galaxy shapes as a precision cosmological tool.



中文翻译:

潮汐中的宇宙学模拟:功率谱、光晕形状响应和形状组装偏差

成熟的分离宇宙技术能够准确校准任何可观测到的对各向同性长波长密度波动的响应。大尺度环境还存在着各向异性地扰动所有可观测物体的潮汐模式。与在单独的宇宙中一样,长潮汐模式和密度模式都可以被有效的各向异性背景吸收,短模式的相互作用和演化在该背景上相应地发生变化。我们进一步开发了潮汐模拟方法,包括对二阶拉格朗日扰动理论 (2LPT) 的适当修正,以生成模拟的初始条件。我们测量物质功率谱的线性潮汐响应,在我们修改后的 2LPT 的高红移和潮汐模拟的低红移下。我们的结果在质量上与以前的工作一致,但在这两种情况下都表现出数量上的差异。我们还测量了晕圈形状的线性潮汐响应或形状偏差,并找到了它与线性晕圈偏差的普遍关系,我们为此提供了一个拟合公式。此外,类似于装配偏差,我们研究了形状偏差的二次依赖性,并首次发现了对光晕浓度和轴比的依赖性。我们的结果为研究内在对齐作为污染或信息的来源提供了有用的见解。当人们使用星系形状的内在对齐作为一种精确的宇宙学工具时,需要正确考虑这些影响。并找到它与线性晕偏差的普遍关系,我们为此提供了一个拟合公式。此外,类似于装配偏差,我们研究了形状偏差的二次依赖性,并首次发现了对光晕浓度和轴比的依赖性。我们的结果为研究内在对齐作为污染或信息的来源提供了有用的见解。当人们使用星系形状的内在对齐作为一种精确的宇宙学工具时,需要正确考虑这些影响。并找到它与线性晕偏差的普遍关系,我们为此提供了一个拟合公式。此外,类似于装配偏差,我们研究了形状偏差的二次依赖性,并首次发现了对光晕浓度和轴比的依赖性。我们的结果为研究内在对齐作为污染或信息的来源提供了有用的见解。当人们使用星系形状的内在对齐作为一种精确的宇宙学工具时,需要正确考虑这些影响。我们的结果为研究内在对齐作为污染或信息的来源提供了有用的见解。当人们使用星系形状的内在对齐作为一种精确的宇宙学工具时,需要正确考虑这些影响。我们的结果为研究内在对齐作为污染或信息的来源提供了有用的见解。当人们使用星系形状的内在对齐作为一种精确的宇宙学工具时,需要正确考虑这些影响。

更新日期:2021-04-16
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