Understanding the nature of luminous red galaxies (LRGs): connecting LRGs to central and satellite subhaloes
Understanding the nature of luminous red galaxies (LRGs): connecting LRGs to central and satellite subhaloes
复制标题
了解发光红色星系 (LRG) 的性质：将 LRG 与中央和卫星亚晕连接起来
DOI：
10.1093/mnras/stt981
复制
发表时间：
2013
期刊：
影响因子：
--
通讯作者：
N. Sugiyama
中科院分区：
文献类型：
--
作者：
S. Masaki;C. Hikage;M. Takada;D. N. Spergel;N. Sugiyama
我们开发了一种新的丰度匹配方法来构建斯隆数字天空调查(Λ)中的发光红色星系(LRG)的模拟星表，该方法使用由LRG主导的冷暗物质模型的光晕和次光晕内部体表模拟。由于观测表明LRG是被动演化的大质量早期类型星系，典型的年龄为≳5 Gyr，我们假设模拟的光晕z=2(Z2-光晕)是今天观察到的LRG-HOST亚晕的祖先，我们将每个LRG-2-晕中最紧密结合的粒子标记为LRG‘恒星’。然后，我们按照z2晕质量的降序识别包含这些恒星toz=0.3(SDSS红移)的子晕，直到匹配的子晕的平均数密度与SDSS LRGs的测量数密度相当。一旦上述规定被确定，我们唯一的自由参数是在z=2时确定的晕数密度，并且该参数被固定以匹配观测到的数密度at z=0.3。通过追踪每个子晕随后的合并和组装历史，我们可以从模拟星表直接计算出z=0.3时中心和卫星LRG的分布及其在每个主机晕中的内部运动。虽然SDSS LRG是通过从SDSS图像中的星等和颜色切割选择的星系，并且不一定是恒星质量选择的样本，但我们的模拟星表再现了SDSS的大量测量结果：中央和卫星LRG的晕占据分布、LRG的投影自相关函数、LRG与背景星系形状的互相关(LRG-星系弱透镜)以及角度平均红移空间功率谱中的非线性红移空间扭曲效应，即上帝之指效应。根据我们的方法生成的模拟星表可以用于消除或校准LRG星系团测量的宇宙学解释中的系统误差，以及理解LRG的性质，如它们的形成和组装历史。
We develop a novel abundance matching method to construct a mock catalogue of luminous red galaxies (LRGs) in the Sloan Digital Sky Survey (SDSS), using catalogues of haloes and subhaloes inN-body simulations for a Λ-dominated cold dark matter model. Motivated by observations suggesting that LRGs are passively evolving, massive early-type galaxies with a typical age ≳5 Gyr, we assume that simulated haloes atz= 2 (z2-halo) are progenitors for LRG-host subhaloes observed today, and we label the most tightly bound particles in each progenitorz2-halo as LRG ‘stars’. We then identify the subhaloes containing these stars toz= 0.3 (SDSS redshift) in descending order of the masses ofz2-haloes until the comoving number density of the matched subhaloes becomes comparable to the measured number density of SDSS LRGs,. Once the above prescription is determined, our only free parameter is the number density of haloes identified atz= 2 and this parameter is fixed to match the observed number density atz= 0.3. By tracing subsequent merging and assembly histories of each progenitorz2-halo, we can directly compute, from the mock catalogue, the distributions of central and satellite LRGs and their internal motions in each host halo atz= 0.3. While the SDSS LRGs are galaxies selected by the magnitude and colour cuts from the SDSS images and are not necessarily a stellar-mass-selected sample, our mock catalogue reproduces a host of SDSS measurements: the halo occupation distribution for central and satellite LRGs, the projected autocorrelation function of LRGs, the cross-correlation of LRGs with shapes of background galaxies (LRG–galaxy weak lensing) and the non-linear redshift-space distortion effect, the Finger-of-God effect, in the angle-averaged redshift-space power spectrum. The mock catalogue generated based on our method can be used for removing or calibrating systematic errors in the cosmological interpretation of LRG clustering measurements as well as for understanding the nature of LRGs such as their formation and assembly histories.