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arXiv 1707.09689astro-ph.GA
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用强透镜拟合DM晕的总密度分布

The total density profile of DM halos fitted from strong lensing

Lin Wang, Da-Ming Chen

摘要:

在宇宙学N体模拟中,重子对冷暗物质晕的影响可以用来解决$Λ$冷暗物质宇宙学中的小尺度问题,如尖核问题和卫星丢失问题.结果表明,对于质量范围从矮星系到星系团的晕,得到的总密度剖面(重子+CDM)比NFW剖面更能与观测的自转曲线相匹配。然而,在我们以前的工作中,我们发现这样的密度分布与最近的强引力透镜观测结果不符。在本文中,我们做相反的:我们拟合最近的强透镜观测与预测的透镜概率的基础上所谓的$(α,β,γ)$双幂律轮廓,并使用最佳拟合参数($α=3.04, β=1.39, γ=1.88$)来计算旋转曲线。我们发现,在一个典型的星系的外部,旋转曲线计算与我们的拟合密度分布远低于观测和那些基于模拟,包括NFW配置文件。这再次验证和加强了我们以前工作中的结论:在$Λ$ CDM范式中,转动曲线观测与强引力透镜观测之间的矛盾是难以调和的。

英文摘要:

In cosmological N-body simulations, the baryon effects on the cold dark matter (CDM) halos can be used to solve the small scale problems in $Λ$CDM cosmology, such as cusp-core problem and missing satellites problem. It turns out that the resultant total density profiles (baryons plus CDM), for halos with mass ranges from dwarf galaxies to galaxy clusters, can match the observations of the rotation curves better than NFW profile. In our previous work, however, we found that such density profiles fail to match the most recent strong gravitational lensing observations. In this paper, we do the converse: we fit the most recent strong lensing observations with the predicted lensing probabilities based on the so-called $(α,β,γ)$ double power-law profile, and use the best-fit parameters ($α=3.04, β=1.39, γ=1.88$) to calculate the rotation curves. We find that, at outer parts for a typical galaxy, the rotation curve calculated with our fitted density profile is much lower than observations and those based on simulations, including the NFW profile. This again verifies and strengthen the conclusions in our previous works: in $Λ$CDM paradigm, it is difficult to reconcile the contradictions between the observations for rotation curves and strong gravitational lensing.

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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