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arXiv 0809.5172astro-ph
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利用Sunyaev-Zel'dovich效应探测星系群中的热气体

Detection of Hot Gas in Galaxy Groups via the Sunyaev-Zel'dovich Effect

K. Moodley, R. Warne, N. Goheer, H. Trac

摘要:

由于在局域宇宙中观测到的重子短缺,我们研究了高分辨率宇宙微波背景(CMB)实验探测附近群晕外部区域热气体的能力。我们构造了热气体模型,气体与暗物质处于流体静力学平衡,并由多方状态方程描述。我们还考虑模型,增加熵的气体符合X射线观测的约束。我们计算的热Sunyaev-Zel'dovich(SZ)信号在这些晕,并将其与预期的灵敏度即将SZ调查实验,如ACT,普朗克和SPT。使用多频维纳滤波器,我们推导出在银河系和河外前景以及宇宙微波背景存在的情况下,SZ的可探测性极限与晕质量和红移的函数关系。我们发现,在z < 0.05时,可以探测到位力质量低于1e14M_solar的群大小的晕,在z < 0.01时,阈值质量下降到3- 4e13M_solar。因此,通过这些CMB实验,可以将附近群大小的晕的SZ失真映射到维里半径上,超出了X射线观测的灵敏度极限。这些测量将提供一个独特的探测群晕外部区域的热气体,深入了解当地的重子普查和非引力反馈的熵注入群内介质。

英文摘要:

Motivated by the observed shortfall of baryons in the local universe, we investigate the ability of high resolution cosmic microwave background (CMB) experiments to detect hot gas in the outer regions of nearby group halos. We construct hot gas models with the gas in hydrostatic equilibrium with the dark matter and described by a polytropic equation of state. We also consider models that add entropy to the gas in line with constraints from X-ray observations. We calculate the thermal Sunyaev-Zel'dovich (SZ) signal in these halos and compare it to the anticipated sensitivities of forthcoming SZ survey experiments such as ACT, PLANCK and SPT. Using a multi-frequency Wiener filter we derive SZ detectability limits as a function of halo mass and redshift in the presence of galactic and extragalactic foregrounds and the CMB. We find that group-sized halos with virial masses below 1e14 M_solar can be detected at z < 0.05 with the threshold mass dropping to 3-4e13 M_solar at z < 0.01. The SZ distortion of nearby group-sized halos can thus be mapped out to the virial radius by these CMB experiments, beyond the sensitivity limits of X-ray observations. These measurements will provide a unique probe of hot gas in the outer regions of group halos, shedding insight into the local census of baryons and the injection of entropy into the intragroup medium from non-gravitational feedback.

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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