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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。 相似文献
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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.而这一问题的解决将有可能带来基础研究上的重大突破 相似文献
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粒子物理学的研究对象是基本粒子,其尺度范围小于10-13cm,质量小于 10-23g,是所谓的微观物理学.宇宙学的最小研究对象是星系,其尺度范围大于 1019cm,质量大于1039g,是所谓的宇观物理学.热大爆炸宇宙模型使两者发生了密切的联系.近十几年来,这种联系日益深化,一方面使宇宙学臻于成熟,另一方面也推动着粒子物理学的发展. 以可靠的物理规律为基础的宇宙学研究,是在有了广义相对论之后才开始的.宇宙的膨胀则是在1929年Hubble发现了河外星系的退行规律后才逐渐被认识的.四十年代末,Gamow及其合作者以宇宙膨胀的观念为基础,首先成功地讨论了宇宙… 相似文献
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Sanjay Oli 《中国物理快报》2009,26(1):40-42
We present some classes of solutions for dust matter coupled to the string cloud in five-dimensional Kaluza-Klein spacetimes. The solutions have one or two distinct singularities depending upon the sign of the constant of integration. Some of the classes of models exhibit inflation in the initial stage. The behaviour of associated parameters has been discussed in detail. 相似文献
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We present a new exactly solvable inflation model in which inflation can stop automatically,and in the approximately de sitter limit,we give its power spectrum which can be tested in the future observations of cosmic microwave background anisotropy. 相似文献
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90年代天体物理对物理学的挑战 总被引:2,自引:0,他引:2
论述了现代天体物理与物理学的密切关系,进而介绍了90年代天体物理的新望远镜和新观测设备,概要地论述了90年代天体物理的重要发现和重大事件,并重点讨论了宇宙学的新进展,最后论述了未来天体物理的主攻方向。 相似文献
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We investigate the constraints on a generalized Chaplygin gas (GCG) model using the gold sample type-Ia supernovae (She Ia) data, the new Supernova Legacy Survey (SNLS) Sne Ia data and the size of baryonic acoustic oscillation peak found in Sloan Digital Sky Survey (SDSS). In a spatially flat universe case we obtain, at a 95.4% confidence level, A8 = 0.76^+0.07 -0.07 and α= 0.028^+0.322 -0.2382 Our results are consistent with the ACDM model (α= 0), but rule out the standard Chaplygin gas model (α= 1). 相似文献
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1998年6月2日,人类第一台大型太空磁谱仪———阿尔法磁谱仪(AlphaMagnenticSpectrometer,简称AMS)搭乘“发现号”航天飞机升空,中央电视台对发射实况进行了现场直播,引起了中国公众的广泛兴趣.那么,AMS的科学目标到底是什... 相似文献
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Selection statics of the Akaike information criterion (AIC) model and the Bayesian information criterion (BIC) model are applied to the A-cold dark matter (ACDM) cosmological model, the constant equation of state of dark energy, w =constant, and the parametrized equation of state of dark energy, w(z) = wo + wlz/(1 + z), to determine which one is the better cosmological model to describe the evolution of the universe by combining the recent cosmic observational data including She Ia, the size of baryonic acoustic oscillation (BAO) peak from SDSS, the three-year WMAP CMB shift parameter. The results show that AIC, BIC and current datasets are not powerful enough to discriminate one model from the others, though odds suggest differences between them. 相似文献
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暗物质是宇宙的主要物质成分,但其本质是什么仍然是现代科学亟待解决的一个重大问题。粒子物理学提供了多种暗物质粒子的候选者,不同的暗物质模型在宇宙小尺度结构方面有迥然不同的预言,所以原则上人们可以通过天文观测来限制暗物质粒子的属性。文章首先综述了暗物质粒子属性对宇宙结构形成的影响,然后阐述目前流行的冷暗物质宇宙学模型面临的一些困难,最后讨论用天文学区分冷、温暗物质模型的天文学方面研究进展情况。 相似文献
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从历史角度,依据史实论述了本世纪20年代初前苏联数学家弗里德曼在爱因斯坦广义相对论的基础上,建立时空为动态的宇宙模型,提出宇宙不稳膨胀的理论,发展并完善了相对论对宇宙的解释,以及对现代演化宇宙学作出的重要贡献。 相似文献
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Cosmological measurements suggest that our universe contains a dark energy component. In order to study the dark energy evolution, we constrain a parameterized dark energy equation of state ω(z) = ω0 + ω1 1+z/z using the recent observational datasets: 157 Gold type Ia supernovae and the newly released 182 Gold type Ia supernovae by the maximum likelihood method. It is found that the best fit ω(z) crosses -1 in the past and the present best fit value of ω(0) 〈 -1 obtained from 157 Gold-type Ia supernovae. The crossing of-1 is not realized and ω0 = -1 is not ruled out in 1σ confidence level for the 182 Gold-type Ia supernovae. It is also found that the range of parameter ω0 is wide even in 1σ confidence level and the best fit ω(z) is sensitive to the prior of Ωm. 相似文献
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Bianchi .Type-I Massive String Magnetized Barotropic Perfect Fluid Cosmological Model in General Relativity
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BALI Raj PAREEK Umesh Kumar PRADHAN Anirudh 《中国物理快报》2007,24(8):2455-2458
Bianchi type-I massive string cosmological model with magnetic field of barotropic perfect fluid distribution through the techniques used by Latelier and Stachel is investigated. To obtain the deterministic model of the universe, it is assumed that the universe is filled with barotropic perfect fluid distribution. The magnetic field is due to electric current produced Mong the x-axis with infinite electrical conduictivity. The behaviour of the model in the presence and absence of magnetic field together with other physical aspects is further discussed. 相似文献