标题： MS0302+17红移为0.42的超星系团的测光和弱引力透镜分析 显示英文标题

标题： A Photometric and Weak Lensing Analysis of the z=0.42 Supercluster MS0302+17

摘要： 我们对红移为0.42的超星系团MS0302+17进行了弱透镜和光度研究，使用在CFHT上用UH8K CCD马赛克相机拍摄的深I和V波段图像。我们使用存档的ROSAT HRI数据来估计流量、气体质量，并在一个案例中估计三个主要星系团的结合质量。然后我们利用CCD数据来确定星系团的光学丰富度和亮度，并绘制出超星系团以及其它前景和背景结构中早型星系的空间分布。我们从样本中的\simeq 30,000个暗背景星系测量引力剪切，在22 < m_I < 26范围内，发现这与如果早型星系以M/L_B\simeq 250 h来追踪质量时所预测的剪切强烈相关。我们进行质量面密度的二维重建。这些重建恢复了所有主要的星系聚集区域，并表明超星系团的大部分质量，如同早型星系一样，集中在三个X射线星系团中，我们得到星系团的平均质光比为M/L_B\simeq 260 h。将测得的质量面密度与从早型星系分布预测的质量面密度进行交叉相关，在零滞后处显示出一个强烈的峰值（显著性达到\simeq 9倍标准差），在分离度\gsim 200 h^{-1}kpc处，早型星系非常准确地追踪了质量。 这个结论得到了傅里叶空间中的互相关支持；我们没有发现M/L或“偏差”随尺度变化的明显证据，从最长波长模式\lambda = 1.5 -6 h^{-1}Mpc来看，我们得到M/L \simeq (280 \pm 40)h，与在星系团中心得到的结果非常相似。我们讨论这些结果对宇宙学密度参数的意义。 显示英文摘要

摘要： We perform a weak lensing and photometric study of the z=0.42 supercluster MS0302+17 using deep I and V band images taken with the UH8K CCD mosaic camera at the CFHT. We use archival ROSAT HRI data to estimate fluxes, gas masses and, in one case, the binding mass of the three major clusters. We then use our CCD data to determine the optical richness and luminosities of the clusters and to map out the spatial distribution of the early type galaxies in the supercluster and in other foreground and background structures. We measure the gravitational shear from a sample of \simeq 30,000 faint background galaxies in the range 22 < m_I < 26 and find this correlates strongly with that predicted from the early type galaxies if they trace the mass with M/L_B \simeq 250 h. We make 2-dimensional reconstructions of the mass surface density. These recover all of the major concentrations of galaxies and indicate that most of the supercluster mass, like the early type galaxies, is concentrated in the three X-ray clusters, and we obtain mean mass-to-light ratios for the clusters of M/L_B \simeq 260 h. Cross-correlation of the measured mass surface density with that predicted from the early type galaxy distribution shows a strong peak at zero lag (significant at the \simeq 9-sigma level), and that at separations \gsim 200 h^{-1}$kpc the early galaxies trace the mass very accurately. This conclusion is supported by cross-correlation in Fourier space; we see little evidence for any variation of M/L or `bias' with scale, and from the longest wavelength modes with \lambda = 1.5-6 h^{-1}Mpc we find M/L \simeq (280 \pm 40)h, quite similar to that obtained for the cluster centers. We discuss the implication of these results for the cosmological density parameter.