ARGO-YBJ实验的中心区域(5000M2)已于2006年6月底完成安装调试并投入试运行。相应的环境监测系统Detector Control System(DCS)也开始工作,持续不断地记录下实验厅内外的温度、厅内的气压、RPC漏电流等参数。通过对这些参数数据的分析,...ARGO-YBJ实验的中心区域(5000M2)已于2006年6月底完成安装调试并投入试运行。相应的环境监测系统Detector Control System(DCS)也开始工作,持续不断地记录下实验厅内外的温度、厅内的气压、RPC漏电流等参数。通过对这些参数数据的分析,可以清楚地了解探测器的工作状况,以维持整个阵列长期稳定运行,同时为理解实验数据和物理分析工作提供参考。展开更多
By adopting the differential age method, we select 17 832 luminous red galaxies from the Sloan Digital Sky Survey Data Release Seven covering redshift 0 〈 z 〈 0.4 to measure the Hubble parameter. Using the full spec...By adopting the differential age method, we select 17 832 luminous red galaxies from the Sloan Digital Sky Survey Data Release Seven covering redshift 0 〈 z 〈 0.4 to measure the Hubble parameter. Using the full spectrum fitting package UZySS, these spectra are reduced with single stellar population models and optimal age information from our selected sample is derived. With the decreasing age-redshift relation, four new observational H（z） data （OHD） points are obtained, which are H（z） = 69.0 ± 19.6 km s^-1 Mpc^-1 at z = 0.07, H（z） = 68.6± 26.2 km s^-1 Mpc^-1 at z = 0.12, H（z）=72.9 ± 29.6 km s^-1 Mpc^-1 at z = 0.2 and H（z）=88.8 ± 36.6 km s^-1 Mpc^-1 at z = 0.28, respectively. Combined with 21 other available OHD data points, the performance of the constraint on both flat and non-flat ACDM models is presented.展开更多
The universe content is considered as a non-perfect fluid with bulk viscosity and is described by a more general equation of state （endowed some deviation from the conventionally assumed cosmic perfect fluid model）....The universe content is considered as a non-perfect fluid with bulk viscosity and is described by a more general equation of state （endowed some deviation from the conventionally assumed cosmic perfect fluid model）. We assume the bulk viscosityis a linear combination of two terms： one is constant, and the other is proportional to the scalar expansion 0 = 3a/a. The equation of state is described as p = （γ - 1）p ＋ po, where po is a parameter. In this framework we demonstrate that this model can be used to explain the dark energy dominated universe, and different proper choices of the parameters may lead to three kinds of fates of the cosmological evolution： no future singularity, big rip, or Type-Ⅲ singularity as presented in IS. Nojiri, S.D. Odintsov, and S. Tsujikawa, Phys. Rev. D 71 （2005） 063004].展开更多
The best physical and geometrical parameters of the main sequence close visual binary system(CVBS), HIP 105947, are presented. These parameters have been constructed conclusively using Al-Wardat’s complex method for ...The best physical and geometrical parameters of the main sequence close visual binary system(CVBS), HIP 105947, are presented. These parameters have been constructed conclusively using Al-Wardat’s complex method for analyzing CVBSs, which is a method for constructing a synthetic spectral energy distribution(SED) for the entire binary system using individual SEDs for each component star. The model atmospheres are in its turn built using the Kurucz(ATLAS9) line-blanketed plane-parallel models. At the same time, the orbital parameters for the system are calculated using Tokovinin’s dynamical method for constructing the best orbits of an interferometric binary system. Moreover, the mass-sum of the components, as well as the ?θ and ?ρ residuals for the system, is introduced. The combination of Al-Wardat’s and Tokovinin’s methods yields the best estimations of the physical and geometrical parameters. The positions of the components in the system on the evolutionary tracks and isochrones are plotted and the formation and evolution of the system are discussed.展开更多
We apply our sky map reconstruction method for transit type interferometers to the Tianlai cylin- der array. The method is based on spherical harmonic decomposition, and can be applied to a cylindrical array as well a...We apply our sky map reconstruction method for transit type interferometers to the Tianlai cylin- der array. The method is based on spherical harmonic decomposition, and can be applied to a cylindrical array as well as dish arrays and we can compute the instrument response, synthesized beam, transfer func- tion and noise power spectrum. We consider cylinder arrays with feed spacing larger than half a wavelength and, as expected, we find that the arrays with regular spacing have grating lobes which produce spurious images in the reconstructed maps. We show that this problem can be overcome using arrays with a different feed spacing on each cylinder. We present the reconstructed maps, and study the performance in terms of noise power spectrum, transfer function and beams for both regular and irregular feed spacing configura- tions.展开更多
文摘ARGO-YBJ实验的中心区域(5000M2)已于2006年6月底完成安装调试并投入试运行。相应的环境监测系统Detector Control System(DCS)也开始工作,持续不断地记录下实验厅内外的温度、厅内的气压、RPC漏电流等参数。通过对这些参数数据的分析,可以清楚地了解探测器的工作状况,以维持整个阵列长期稳定运行,同时为理解实验数据和物理分析工作提供参考。
基金supported by the National Natural Science Foundation of China
文摘By adopting the differential age method, we select 17 832 luminous red galaxies from the Sloan Digital Sky Survey Data Release Seven covering redshift 0 〈 z 〈 0.4 to measure the Hubble parameter. Using the full spectrum fitting package UZySS, these spectra are reduced with single stellar population models and optimal age information from our selected sample is derived. With the decreasing age-redshift relation, four new observational H（z） data （OHD） points are obtained, which are H（z） = 69.0 ± 19.6 km s^-1 Mpc^-1 at z = 0.07, H（z） = 68.6± 26.2 km s^-1 Mpc^-1 at z = 0.12, H（z）=72.9 ± 29.6 km s^-1 Mpc^-1 at z = 0.2 and H（z）=88.8 ± 36.6 km s^-1 Mpc^-1 at z = 0.28, respectively. Combined with 21 other available OHD data points, the performance of the constraint on both flat and non-flat ACDM models is presented.
基金The project partly supported by National Natural Science Foundation of China under Grant No. 10675062 and the Doctoral Foundation of China We thank Profs. I. Brevik, S.D. 0dintsov, and Lewis H. Ryder for lots of interesting discussions.
文摘The universe content is considered as a non-perfect fluid with bulk viscosity and is described by a more general equation of state （endowed some deviation from the conventionally assumed cosmic perfect fluid model）. We assume the bulk viscosityis a linear combination of two terms： one is constant, and the other is proportional to the scalar expansion 0 = 3a/a. The equation of state is described as p = （γ - 1）p ＋ po, where po is a parameter. In this framework we demonstrate that this model can be used to explain the dark energy dominated universe, and different proper choices of the parameters may lead to three kinds of fates of the cosmological evolution： no future singularity, big rip, or Type-Ⅲ singularity as presented in IS. Nojiri, S.D. Odintsov, and S. Tsujikawa, Phys. Rev. D 71 （2005） 063004].
基金the Human Development Fund for the scholarshipHadhramout University in Yemen for ongoing support
文摘The best physical and geometrical parameters of the main sequence close visual binary system(CVBS), HIP 105947, are presented. These parameters have been constructed conclusively using Al-Wardat’s complex method for analyzing CVBSs, which is a method for constructing a synthetic spectral energy distribution(SED) for the entire binary system using individual SEDs for each component star. The model atmospheres are in its turn built using the Kurucz(ATLAS9) line-blanketed plane-parallel models. At the same time, the orbital parameters for the system are calculated using Tokovinin’s dynamical method for constructing the best orbits of an interferometric binary system. Moreover, the mass-sum of the components, as well as the ?θ and ?ρ residuals for the system, is introduced. The combination of Al-Wardat’s and Tokovinin’s methods yields the best estimations of the physical and geometrical parameters. The positions of the components in the system on the evolutionary tracks and isochrones are plotted and the formation and evolution of the system are discussed.
基金supported by the MOST 863 program(Grant 2012AA121701)the CAS Repair and Procurement grant+4 种基金supported by PNCG,Observatoire de Paris,Irfu/CEA and LAL/CNRSsupported by the China Scholarship Councilsupported by the CAS Strategic Priority Research Program(XDB09020301)the National Natural Science Foundation of China(NSFC,Grant 11373030)supported by the NSFC(Grant 11473044)
文摘We apply our sky map reconstruction method for transit type interferometers to the Tianlai cylin- der array. The method is based on spherical harmonic decomposition, and can be applied to a cylindrical array as well as dish arrays and we can compute the instrument response, synthesized beam, transfer func- tion and noise power spectrum. We consider cylinder arrays with feed spacing larger than half a wavelength and, as expected, we find that the arrays with regular spacing have grating lobes which produce spurious images in the reconstructed maps. We show that this problem can be overcome using arrays with a different feed spacing on each cylinder. We present the reconstructed maps, and study the performance in terms of noise power spectrum, transfer function and beams for both regular and irregular feed spacing configura- tions.
