The luminosity‐weighted or ‘marked’ correlation function
The luminosity‐weighted or ‘marked’ correlation function
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DOI：
10.1111/j.1365-2966.2006.10196.x
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发表时间：
2005-12
影响因子：
4.8
通讯作者：
R. Skibba;R. Sheth;A. Connolly;R. Scranton
中科院分区：
文献类型：
--
作者：
R. Skibba;R. Sheth;A. Connolly;R. Scranton
我们介绍了斯隆数字巡天(SDSS)中红移空间光度加权或标记的关联函数的测量结果。这些都与一个模型进行了比较，在该模型中，星团的光度函数和光度依赖与观测到的相同，并且光度加权关联函数的形式完全是大量光晕填充密集区域这一事实的结果。我们通过使用模拟星表来做到这一点，这些星表被限制为再现观测到的光度函数和星系团的光度依赖关系，以及使用红移空间晕模型的语言。这些分析表明，即使没有大尺度的物理影响，显著的相关性也可能在大尺度上显示信号--光晕与其环境之间的统计相关性将产生可测量的信号。我们的模型与测量结果吻合得很好，表明致密区域的晕质量函数是顶重的；晕质量与大尺度环境之间的关联是星系性质与环境关联的主要驱动因素；晕中中心星系的光度不同于(通常比)晕中其他天体的光度。因此，我们的测量为星系形成模型的这三个标准假设的准确性提供了强有力的证据。这些假设也构成了目前基于晕模型的星系团解释的基础。当相同的星系按其u、g或r波段的亮度加权时，显著的关联函数在较红的波段中较强。当重量是星系颜色而不是光度时，数据表明，接近的星系对往往有更红的颜色。这种显著关联的波长相关性与星系形成模型的定性一致，反映了晕中星系的平均光度对r波段的晕质量的依赖比对u波段的依赖更强。我们发现的光度和颜色相关性与星系团中的星系群比场中的星系群更大的模型是一致的。如果u波段光度是恒星形成的可靠示踪，那么我们的结果表明星系团星系的恒星形成率较低。这种环境趋势测量的优点是，它不需要将星系分类为场、群和星系团环境。
We present measurements of the redshift-space luminosity-weighted or ‘marked’ correlation function in the Sloan Digital Sky Survey (SDSS). These are compared with a model in which the luminosity function and luminosity dependence of clustering are the same as that observed, and in which the form of the luminosity-weighted correlation function is entirely a consequence of the fact that massive haloes populate dense regions. We do this by using mock catalogues which are constrained to reproduce the observed luminosity function and the luminosity dependence of clustering, as well as by using the language of the redshift-space halo model. These analyses show that marked correlations may show a signal on large scales even if there are no large-scale physical effects – the statistical correlation between haloes and their environment will produce a measurable signal. Our model is in good agreement with the measurements, indicating that the halo mass function in dense regions is top heavy; the correlation between halo mass and large-scale environment is the primary driver for correlations between galaxy properties and environment; and the luminosity of the central galaxy in a halo is different from (in general, brighter than) that of the other objects in the halo. Thus our measurement provides strong evidence for the accuracy of these three standard assumptions of galaxy formation models. These assumptions also form the basis of current halo-model-based interpretations of galaxy clustering. When the same galaxies are weighted by their u-, g- or r-band luminosities, then the marked correlation function is stronger in the redder bands. When the weight is galaxy colour rather than luminosity, then the data suggest that close pairs of galaxies tend to have redder colours. This wavelength dependence of marked correlations is in qualitative agreement with galaxy formation models, and reflects the fact that the mean luminosity of galaxies in a halo depends more strongly on halo mass in the r-band than in u. The luminosity and colour dependence we find are consistent with models in which the galaxy population in clusters is more massive than the population in the field. If the u-band luminosity is a reliable tracer of star formation, then our results suggest that cluster galaxies have lower star formation rates. The virtue of this measurement of environmental trends is that it does not require classification of galaxies into field, group and cluster environments.