高红移Ⅰ_a型超新星的搜寻和宇宙的加速膨胀

HIGHz Ⅰ a SUPERNOVAE SEARCH AND THE ACCELERATION OF THE COSMIC EXPANSION

观测研究表明，Ⅰａ型超新星可以作为宇宙距离测量的标准光源．天文学家还从近邻Ⅰａ型超新星光变的研究中得出可靠地确定其最高光度的方法．在此基础上，国际上两个相互竞争的研究集体经过几年的不懈努力，对高红移超新星进行了搜寻和观测．他们各自独立地得到了相同的结论：宇宙学常数Λ＞０，宇宙在加速膨胀．这项研究结果将对宇宙学，星系和大尺度结构的形成和演化的研究产生重要影响．更重要的是，它把所谓“宇宙学常数问题”提到我们面前，不再能够回避．

Observations of nearby supernovae show that supernovae Ⅰ a can be taken as standard sources for the measurement of distance on cosmological scales.Survey of the nearby supernovae Ⅰ a provides a reliable method to determine the peak luminosity of supernovae Ⅰ a with their light curves.Based on this,two rival international groups began to search for and observe high-z supernovae Ⅰ a several years ago.In 1998,both groups came up with the same conclusion: the cosmological constant Λ >0,or the expansion of the universe is accelerating.This result has an important bearing on cosmology,the formation and evolution of the galaxy and the large-scale structure.More importantly,it brought forward the “problem of the cosmological constant”,not to be evaded any more.Solution of this issue may lead to a major breakthrough in the fundamental research.