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arXiv 2201.05195astro-ph.COgr-qc
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暗物质粒子产生宇宙学中的结构形成

Structure Formation in Dark Matter Particle Production Cosmology

Z. Safari, K. Rezazadeh, B. Malekolkalami

摘要:

我们研究了一个宇宙学场景,其中暗物质粒子可以在宇宙演化过程中产生。将宇宙看作一个开放的热力学系统,利用非平衡态热力学,我们研究了引力粒子产生的机制。在这个系统中,我们研究了牛顿扰动体系中宇宙大尺度结构(LSS)的形成,并导出了控制暗物质超密度演化的方程。然后,我们实现了普朗克2018 CMB测量,SNe Ia和BAO观测的宇宙学数据,以及Riess等人(2019)对$H_0$的局部测量,为我们的模型参数提供了一些宇宙学约束。我们看到,我们的场景($χ_{\rm tot}^{2}=3834.40$)的最佳情况下,符合观测数据比基线$Λ$ CDM模型($χ_{\rm tot}^{2} = 3838.00$)在背景水平。此外,我们估计的增长因子的线性扰动,并表明,我们的模型($χ_{fσ_{8}}^{2}=39.85$)的最佳情况下,适合LSS数据显着优于$Λ$ CDM模型($χ_{fσ_{8}}^{2}=45.29$)。因此,我们的模型在线性微扰水平上也比标准宇宙学模型有更好的表现。

英文摘要:

We investigate a cosmological scenario in which the dark matter particles can be created during the evolution of the Universe. By regarding the Universe as an open thermodynamic system and using non-equilibrium thermodynamics, we examine the mechanism of gravitational particle production. In this setup, we study the large-scale structure (LSS) formation of the Universe in the Newtonian regime of perturbations and derive the equations governing the evolution of the dark matter overdensities. Then, we implement the cosmological data from Planck 2018 CMB measurements, SNe Ia and BAO observations, as well as the Riess et al. (2019) local measurement for $H_0$ to provide some cosmological constraints for the parameters of our model. We see that the best case of our scenario ($χ_{\rm tot}^{2}=3834.40$) fits the observational data better than the baseline $Λ$CDM model ($χ_{\rm tot}^{2} = 3838.00$) at the background level. We moreover estimate the growth factor of linear perturbations and show that the best case of our model ($χ_{fσ_{8}}^{2}=39.85$) fits the LSS data significantly better than the $Λ$CDM model ($χ_{fσ_{8}}^{2}=45.29$). Consequently, our model also makes a better performance at the level of the linear perturbations compared to the standard cosmological model.

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