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arXiv 1006.2828astro-ph.CO
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Sunyaev-Zel'dovich角功率谱模板

Templates for the Sunyaev-Zel'dovich Angular Power Spectrum

Hy Trac, Paul Bode, Jeremiah P. Ostriker

摘要:

我们提出了模板的Sunyaev-Zel'dovich(SZ)角功率谱的基础上的四个模型的非线性气体分布。频率依赖的SZ温度波动,与热(TSZ)和动力学(KSZ)的贡献,计算通过跟踪通过暗物质模拟,处理包括气体在暗物质晕和星系际介质。不同的晕气体模型进行了比较,研究如何恒星形成,能量反馈,和非热压力支持的影响角功率谱。对标准模型进行了校准,以再现从低红移星系团和星系群测量到的恒星和气体的比例以及X射线标度关系。其他模型说明了目前的理论和经验的不确定性有关的性质的集群内介质。相对于标准模型,它们的角功率谱相差约50%(TSZ),20%(KSZ),和40%(SZ在148 GHz)为l=3000,σ_8 =0.8,和均匀再电离在z=10。角功率谱的振幅随着气体质量和结合能在恒星形成过程中被移除,以及气体被能量反馈推向更大的半径而减小。在非热压力支持下,保持流体静力平衡所需的压力更小,从而减少了对SZ功率的热贡献。我们还计算了SZ模板作为sigma_8的函数,并量化这种依赖性。假设C_1与(sigma_8/0.8)α成比例,对于0.6<sigma_8<1,在1 =3000时,有效缩放指数的范围为7<alpha_tsz<9、4.5<alpha_ksz<5.5和6.5<alpha_sz(148 GHz)<8。模板光谱是公开的,可以使用时,适合的SZ贡献的宇宙微波背景的弧分尺度。

英文摘要:

We present templates for the Sunyaev-Zel'dovich (SZ) angular power spectrum based on four models for the nonlinear gas distribution. The frequency-dependent SZ temperature fluctuations, with thermal (TSZ) and kinetic (KSZ) contributions, are calculated by tracing through a dark matter simulation, processed to include gas in dark matter halos and in the filamentary intergalactic medium. Different halo gas models are compared to study how star formation, energetic feedback, and nonthermal pressure support influence the angular power spectrum. The standard model has been calibrated to reproduce the stellar and gas fractions and X-ray scaling relations measured from low redshift clusters and groups. The other models illustrate the current theoretical and empirical uncertainties relating to properties of the intracluster medium. Relative to the standard model, their angular power spectra differ by approximately 50% (TSZ), 20% (KSZ), and 40% (SZ at 148 GHz) for l=3000, sigma_8=0.8, and homogeneous reionization at z=10. The angular power spectrum decreases in amplitude as gas mass and binding energy is removed through star formation, and as gas is pushed out to larger radii by energetic feedback. With nonthermal pressure support, less pressure is required to maintain hydrostatic equilibrium, thus reducing the thermal contribution to the SZ power. We also calculate the SZ templates as a function of sigma_8 and quantify this dependence. Assuming C_l is proprotional to (sigma_8/0.8)^alpha, the effective scaling index ranges from 7<alpha_tsz<9, 4.5<alpha_ksz<5.5, and 6.5<alpha_sz(148 GHz)<8 at l=3000 for 0.6<sigma_8<1. The template spectra are publicly available and can be used when fitting for the SZ contribution to the cosmic microwave background on arcminute scales.

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