标题： 宇宙学晕：电离星系际介质的搜索 显示英文标题

标题： Cosmological Halos: A Search for the Ionized Intergalactic Medium

摘要： 标准大爆炸核合成预测宇宙的平均重子密度为临界密度的几个百分点。 只观察到了预测重子的十分之一。 缺失的重子可能存在于稀薄电离的星系际介质（IGM）中。 为了测量IGM，我们尝试在强高红移射电源周围寻找汤姆孙散射晕。 对射电源1935-692进行了澳大利亚望远镜紧凑阵列的观测。 我们假设IGM是均匀的，并且1935-692在10^7 - 10^8年期间有各向同性的稳定辐射。 使用了预期晕可见性函数的模型，在\chi ^2拟合中对\Omega _{IGM}设置了上限。 上限取决于用于表征数据系统误差的方法。 结果是 2/sigma限制为\Omega _{IGM} < 0.65。 虽然尚未达到测试原初核合成的灵敏度水平，但技术的改进可能在未来研究中实现这一点。 显示英文摘要

摘要： Standard big bang nucleosynthesis predicts the average baryon density of the Universe to be a few percent of the critical density. Only about one tenth of the predicted baryons have been seen. A plausible respository for the missing baryons is in a diffuse ionized intergalactic medium (IGM). In an attempt to measure the IGM we searched for Thomson-scattered halos around strong high redshift radio sources. Observations of the radio source 1935-692 were made with the Australia Telescope Compact Array. We assumed a uniform IGM, and isotropic steady emission of 1935-692 for a duration between 10^7 - 10^8 years. A model of the expected halo visibility function was used in \chi^2 fits to place upper limits on \Omega_{IGM}. The upper limits varied depending on the methods used to characterize systematic errors in the data. The results are 2/sigma limits of \Omega_{IGM} < 0.65. While not yet at the sensitivity level to test primordial nucleosynthesis, improvements on the technique will probably allow this in future studies.