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arXiv 2005.13990astro-ph.CO
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检验高红移处的宇宙曲率:结合LSST强引力透镜系统与作为新标准烛光的类星体

Testing the cosmic curvature at high redshifts: the combination of LSST strong lensing systems and quasars as new standard candles

Tonghua Liu, Shuo Cao, Jia Zhang, Marek Biesiada, Yuting Liu, Yujie Lian

AI总结:

提出结合高红移类星体(新标准烛光)与LSST强引力透镜系统的模型无关方法约束宇宙曲率,在高红移实现高精度约束,并发现透镜质量分布对结果影响显著。

摘要:

宇宙曲率作为宇宙学的基本参数,可能为暴胀和宇宙起源提供深层线索。我们提出了一种改进的与模型无关的方法,通过将高红移类星体构建的Hubble图与即将开展的LSST巡天预期观测到的星系尺度强引力透镜系统相结合,来约束宇宙曲率。更具体地说,最新的类星体数据被用作 $0.036<z<5.100$ 范围内的一种新型标准烛光,其光度距离可以直接从X射线和UV光度之间的非线性关系中推导出来。与其他方法相比,所提出的涉及类星体数据的方法在高红移($z\sim 5.0$)处实现了更高精度的约束($ΔΩ_k\sim 10^{-2}$)。我们还在强引力透镜研究中广泛使用的三种透镜模型框架(SIS模型、幂律球模型和扩展幂律透镜模型)内考察了透镜质量分布的影响,发现宇宙曲率与透镜模型参数之间存在强相关性。当假设采用幂律质量密度剖面时,可获得对宇宙曲率 $Ω_k$ 最严格的约束。因此,早型星系中的质量密度剖面问题仍然是一个需要进一步研究的关键问题。

英文摘要:

The cosmic curvature, a fundamental parameter for cosmology could hold deep clues to inflation and cosmic origins. We propose an improved model-independent method to constrain the cosmic curvature by combining the constructed Hubble diagram of high-redshift quasars with galactic-scale strong lensing systems expected to be seen by the forthcoming LSST survey. More specifically, the most recent quasar data are used as a new type of standard candles in the range $0.036<z<5.100$, whose luminosity distances can be directly derived from the non-linear relation between X-ray and UV luminosities. Compared with other methods, the proposed one involving the quasar data achieves constraints with higher precision ($ΔΩ_k\sim 10^{-2}$) at high redshifts ($z\sim 5.0$). We also investigate the influence of lens mass distribution in the framework of three types of lens models extensively used in strong lensing studies (SIS model, power-law spherical model, and extended power-law lens model), finding the strong correlation between the cosmic curvature and the lens model parameters. When the power-law mass density profile is assumed, the most stringent constraint on the cosmic curvature $Ω_k$ can be obtained. Therefore, the issue of mass density profile in the early-type galaxies is still a critical one that needs to be investigated further.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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