On the Mass-to-Light Ratio of Large-Scale Structure
On the Mass-to-Light Ratio of Large-Scale Structure
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DOI：
10.1086/432084
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发表时间：
2004-11
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影响因子：
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通讯作者：
J. Tinker;D. Weinberg;Zheng Zheng-Zheng;I. Zehavi
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文献类型：
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作者：
J. Tinker;D. Weinberg;Zheng Zheng-Zheng;I. Zehavi
我们在一些模型中研究了大尺度结构的质光比（M/L）对宇宙学参数的依赖性，这些模型受到约束以匹配投影星系相关函数\(w_p(r_p)\)和星系光度函数的观测结果。对于一系列具有固定的、基于观测的幂律谱形状且归一化参数\(\sigma_8\)逐渐增大的宇宙学模型，我们找到了星系晕占据分布（HOD）的参数，这些参数能够重现斯隆数字巡天（SDSS）中作为光度函数的\(w_p(r_p)\)测量值。从这些HOD模型中，我们计算了r波段条件光度函数\(\varPhi(L|M_h)\)，并由此得到了作为晕质量\(M_h\)函数的平均质光比。我们还使用\(\varPhi(L|M_h)\)在N体模拟的晕中填充星系，从而在一系列大尺度环境（包括星系团吸积区域）中计算质光比。对于所有宇宙学模型，高质量晕或高密度区域中的质光比大致与晕质量或平滑尺度无关。然而，质光比的“平台”值除了与物质密度参数\(\varOmega_m\)明显成比例外，还取决于\(\sigma_8\)，并且它仅对于星系相关函数近似无偏的模型（即\(\sigma_8\approx\sigma_{8g}\)）才代表通用值\(\langle M/L\rangle=\varOmega_m\rho_{crit}/\rho_{lum}\)。我们对于星系团质量晕的结果遵循趋势\((M/L)_{cl}=577(\varOmega_m/0.3)(\sigma_8/0.9)^{1.7}hM_{\odot}/L_{\odot}\)。结合加拿大天体物理研究所（CNOC）星系团的平均质光比，该关系意味着\((\sigma_8/0.9)(\varOmega_m/0.3)^{0.6}=0.75\pm0.06\)。斯隆数字巡天星系团以及凯恩斯巡天（CAIRNS）中星系团的维里区域的质光比估计值意味着\(\sigma_8\varOmega\)有类似的值，而凯恩斯巡天对星系团吸积区域的估计值则意味着一个较低的值。这些结果与近期对宇宙微波背景测量和其他大尺度结构数据的联合分析所青睐的参数值\(\varOmega_m\approx0.3\)，\(\sigma_8\approx0.9\)不一致，尽管它们与范登博施等人对2度视场星系红移巡天（2dF Galaxy Redshift Survey）的分析所推断的值一致。我们讨论了这种差异可能的解决方案，但似乎没有一个是完全令人满意的。在附录中，我们给出了一个基于我们的3603个N体模拟校准的晕偏置因子的改进公式，以及一种从给定的宇宙学模型和HOD计算星系相关函数的改进分析技术。
We examine the dependence of the mass-to-light (M/L) ratio of large-scale structure on cosmological parameters, in models that are constrained to match observations of the projected galaxy correlation function wp(rp) and the galaxy luminosity function. For a sequence of cosmological models with a fixed, observationally motivated power spectrum shape and increasing normalization σ8, we find parameters of the galaxy halo occupation distribution (HOD) that reproduce wp(rp) measurements as a function of luminosity from the Sloan Digital Sky Survey (SDSS). From these HOD models we calculate the r-band conditional luminosity function Φ(L|Mh), and from this the mean M/L ratio as a function of halo mass Mh. We also use Φ(L|Mh) to populate halos of N-body simulations with galaxies and thereby compute M/L in a range of large-scale environments, including cluster infall regions. For all cosmological models, the M/L ratio in high-mass halos or high-density regions is approximately independent of halo mass or smoothing scale. However, the "plateau" value of M/L depends on σ8 in addition to the obvious proportionality with the matter density parameter Ωm, and it represents the universal value ⟨M/L⟩ = Ωmρcrit/ρlum only for models in which the galaxy correlation function is approximately unbiased, i.e., with σ8 ≈ σ8g. Our results for cluster mass halos follow the trend (M/L)cl = 577(Ωm/0.3)(σ8/0.9)1.7 h M☉/L☉. Combined with the mean M/L ratio for CNOC galaxy clusters, this relation implies (σ8/0.9)(Ωm/0.3)0.6 = 0.75 ± 0.06. M/L estimates for SDSS clusters and the virial regions of clusters in the CAIRNS survey imply a similar value of σ8Ω, while the CAIRNS estimates for cluster infall regions imply a lower value. These results are inconsistent with parameter values Ωm ≈ 0.3, σ8 ≈ 0.9 favored by recent joint analyses of cosmic microwave background measurements and other large-scale structure data, although they agree with values inferred from the van den Bosch et al. analysis of the 2dF Galaxy Redshift Survey. We discuss possible resolutions of this discrepancy, none of which seems entirely satisfactory. In appendices we present an improved formula for halo bias factors calibrated on our 3603 N-body simulations and an improved analytic technique for calculating the galaxy correlation function from a given cosmological model and HOD.