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中国科学:物理学 力学 天文学（英文版）
中国科学:物理学 力学 天文学（英文版）

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中国科学:物理学 力学 天文学（英文版）/Journal Science China(Physics, Mechanics&Astronomy)CSCDCSTPCDEISCI
查看更多>>《中国科学》是中国科学院主办、中国科学杂志社出版的自然科学专业性学术刊物。《中国科学》任务是反映中国自然科学各学科中的最新科研成果，以促进国内外的学术交流。《中国科学》以论文形式报道中国基础研究和应用研究方面具有创造性的、高水平的和有重要意义的科研成果。在国际学术界，《中国科学》作为代表中国最高水平的学术刊物也受到高度重视。国际上最具有权威的检索刊物SCI，多年来一直收录《中国科学》的论文。1999年《中国科学》夺得国家期刊奖的第一名。
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    Observation of spectral lines in the exceptional GRB 221009A

    Yan-Qiu ZhangShao-Lin XiongJi-Rong MaoShuang-Nan Zhang...
    187-206页
    查看更多>>摘要：As the brightest gamma-ray burst ever observed,GRB 221009A provided a precious opportunity to explore spectral line fea-tures.In this article,we performed a comprehensive spectroscopy analysis of GRB 221009A jointly with GECAM-C and Fermi/GBM data to search for emission and absorption lines.For the first time we investigated the line feature throughout this GRB including the most bright part where many instruments suffered problems,and identified prominent emission lines in multiple time intervals.The central energy of the Gaussian emission line evolves from about 37 to 6 MeV,with a nearly constant ratio(about 10％)between the line width and central energy.Particularly,we find that both the central energy and the energy flux of the emission line evolve with time as a power law decay with power law index of-1 and-2,respectively.We suggest that the observed emission lines most likely origin from the blue-shifted electron positron pair annihilation 511 keV line.We find that a standard high latitude emission scenario cannot fully interpret the observation,thus we propose that the emission line comes from some dense clumps with electron positron pairs traveling together with the jet.In this scenario,we can use the emission line to directly,for the first time,measure the bulk Lorentz factor of the jet(Γ)and reveal its time evolution(i.e.,Γ～t-1)during the prompt emission.Interestingly,we find that the flux of the annihilation line in the co-moving frame keeps constant.These discoveries of the spectral line features shed new and important lights on the physics of GRB and relativistic jet.
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    Improving constraint on Ωm from SDSS using marked correlation functions

    Limin LaiJiacheng DingXiaolin LuoYizhao Yang...
    207-224页
    查看更多>>摘要：Large-scale structure(LSS)surveys will increasingly provide stringent constraints on our cosmological models.Recently,the density-marked correlation function(MCF)has been introduced,offering an easily computable density-correlation statistic.Sim-ulations have demonstrated that MCFs offer additional,independent constraints on cosmological models beyond the standard two-point correlation(2PCF).In this study,we apply MCFs for the first time to SDSS CMASS data,aiming to investigate the statistical information regarding clustering and anisotropy properties in the Universe and assess the performance of various weighting schemes in MCFs,and finally obtain constraints on Ωm.Upon analyzing the CMASS data,we observe that,by combin-ing different weights(α=[-0.2,0,0.2,0.6]),the MCFs provide a tight and independent constraint on the cosmological parameterΩm,yielding Ωm=0.293±0.006 at the 1σ level,which represents a significant reduction in the statistical error by a factor of 3.4 compared to that from 2PCF.Our constraint is consistent with recent findings from the small-scale clustering of BOSS galaxies(Zhai et al.Astronphys.J.948,99(2023))within the 1σ level.However,we also find that our estimate is lower than the Planck measurements by about 2.6σ,indicating the potential presence of new physics beyond the standard cosmological model if all the systematics are fully corrected.The method outlined in this study can be extended to other surveys and datasets,allowing for the constraint of other cosmological parameters.Additionally,it serves as a valuable tool for forthcoming emulator analysis on the Chinese Space Station Telescope(CSST).
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