Galaxy Formation in WDM Cosmology
Galaxy Formation in WDM Cosmology
复制标题
WDM 宇宙学中的星系形成
DOI：
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发表时间：
2012
期刊：
影响因子：
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通讯作者：
A. Lamastra
中科院分区：
文献类型：
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作者：
N. Menci;F. Fiore;A. Lamastra
我们首次使用星系形成的半解析模型研究了暖暗物质（WDM）功率谱对星系统计特性的影响。与标准冷暗物质 (CDM) 情况相比，我们采用作为参考情况的 WDM 光谱被抑制到低于截止尺度 ~ 1 Mpc，对应于质量 m_X=0.75 keV（对于热遗迹 WDM 粒子）。这确保了与微波背景 WMAP 数据以及通过将流体动力学 N 体模拟与观察到的 Lyman-{\alpha} 森林进行比较所提供的当前边界的一致性。我们使用这样的 WDM 光谱运行我们的基准半解析模型，以导出星系光度函数（B、UV 和 K 波段）和大范围宇宙历元的恒星质量分布，以与最近的观测结果和 CDM 情况下的结果进行比较。 WDM 模型中预测的星系颜色分布也会根据数据进行检查。与标准 CDM 情况相比，我们假设 WDM 光谱获得的光度和恒星质量分布具有以下特征：i）暗端斜率变平，ii）z \lesssim 0.8 时明端截止锐化。我们讨论了前一个结果如何与 WDM 场景中较少数量的小质量晕塌陷直接相关，而后者则与较少数量的卫星星系在低红移下积累在大质量晕中有关，从而抑制了中央大质量星系上小块的吸积。这些结果表明，采用 WDM 功率谱可能有助于解决 CDM 星系形成场景的两个主要问题，即低红移（最重要的是高红移）下预测的微弱（低质量）星系过多，以及低红移下明亮（大质量）星系过多。
We investigate for the first time the effects of a Warm Dark Matter (WDM) power spectrum on the statistical properties of galaxies using a semi-analytic model of galaxy formation. The WDM spectrum we adopt as a reference case is suppressed - compared to the standard Cold Dark Matter (CDM) case - below a cut-off scale ~ 1 Mpc corresponding (for thermal relic WDM particles) to a mass m_X=0.75 keV. This ensures consistency with present bounds provided by the microwave background WMAP data and by the comparison of hydrodynamical N-body simulations with observed Lyman-{\alpha} forest. We run our fiducial semi-analytic model with such a WDM spectrum to derive galaxy luminosity functions (in B, UV, and K bands) and the stellar mass distributions over a wide range of cosmic epochs, to compare with recent observations and with the results in the CDM case. The predicted color distribution of galaxies in the WDM model is also checked against the data. When compared with the standard CDM case, the luminosity and stellar mass distributions we obtain assuming a WDM spectrum are characterized by: i) a flattening of the faint end slope and ii) a sharpening of the cutoff at the bright end for z \lesssim 0.8. We discuss how the former result is directly related to the smaller number of low-mass haloes collapsing in the WDM scenario, while the latter is related to the smaller number of satellite galaxies accumulating in massive haloes at low redshift, thus suppressing the accretion of small lumps on the central, massive galaxies. These results shows how a adopting a WDM power spectrum may contribute to solve two major problems of CDM galaxy formation scenarios, namely, the excess of predicted faint (low mass) galaxies at low and - most of all - high redshifts, and the excess of bright (massive) galaxies at low redshifts.
影响因子：
8.7
作者：
Komatsu, E.;Smith, K. M.;Wright, E. L.
通讯作者：
Wright, E. L.