论文标题

Baryon粘贴算法:基于光环和粒子的粘贴方法

Baryon Pasting Algorithm: Halo-based and Particle-based Pasting Methods

论文作者

Osato, Ken, Nagai, Daisuke

论文摘要

我们提出了一种快速的方法论,可以基于仅$ n $ body模拟的暗物质和分析性群集内培养基模型,对热和动力学Sunyaev-Zel'Dovich(SZ)效应进行模拟观察。该方法采用两种不同的方法:基于光晕的粘贴(​​HP)和基于粒子的粘贴(PP)。前者将气体密度和压力粘贴到光晕上,仅需要光晕目录,后者也考虑了场颗粒的贡献,即不属于任何光晕的颗粒,因此使用了完整的粒子信息。因此,PP算法结合了HP算法以外的二级效应:光晕的非球性和弥散气的贡献。特别是,这种弥漫性成分是动力学SZ效应的主要来源。作为对我们方法的验证,我们用HP和108个平面地图制作了108个全套地图,这些地图覆盖了$ 5 \ times 5 \,\ Mathrm {deg}^2 $,以及HP和PP,以及测量的地图功率谱。我们的方法可以在几个小时内生成模拟地图,即使对于具有平行计算环境的全天空覆盖范围也是如此。 HP图的功率光谱与热SZ效应的Halo模型预测一致。另一方面,由于卤代非球质性,PP图的功率光谱被抑制,但可以更好地再现动力学SZ效应的理论预测。我们讨论了Baryon-Pasted模拟SZ地图的实用性,以估算SZ统计的协方差矩阵,并为集群宇宙学的选择和投影效应进行建模。

We present a fast methodology to produce mock observations of the thermal and kinetic Sunyaev-Zel'dovich (SZ) effects based on the dark matter only $N$-body simulations coupled with the analytic intra-cluster medium model. The methods employ two different approaches: halo-based pasting (HP) and particle-based pasting (PP). The former pastes gas density and pressure onto halos and requires only a halo catalogue, and the latter considers the contribution from field particles as well, i.e., particles that do not belong to any halos and thus utilise the full particle information. Therefore, the PP algorithm incorporates secondary effects beyond the HP algorithm: asphericity of halos and contribution from diffuse gas. In particular, such a diffuse component is the dominant source of the kinetic SZ effect. As validation of our methods, we have produced 108 all-sky maps with HP and 108 flat-sky maps, which cover $5 \times 5 \, \mathrm{deg}^2$ with both HP and PP, and measured power spectra of the maps. Our method can produce a mock map within a few hours, even for all-sky coverage with a parallel computational environment. The power spectra of HP maps are consistent with the halo model prediction of the thermal SZ effect. On the other hand, the power spectra of PP maps are suppressed due to the halo asphericity but can reproduce better the theoretical prediction for the kinetic SZ effect. We discuss the utility of baryon-pasted mock SZ maps for estimating the covariance matrix of SZ statistics and modelling the selection and projection effects for cluster cosmology.

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