基於暗能量模型的Sandage-Loeb檢驗

Abstract

迅速發展的空間探測技術為我們研究暗能量、暗物質等宇宙學問題提供了技術支持。在探索暗能量的過程中，所有的假設模型必須要通過實驗得到的觀測數據的檢驗。一般步驟是從理論上預測模型的宇宙學演化行為，然後帶入觀測數據檢查是否一致。 Sandage-Loeb檢驗對應的是測量遙遠天體紅移變化的實驗，這個紅移變化能夠反映宇宙膨脹速度的變化。儘管這個實驗的原理簡單，但卻是被證明了的能夠提供暗能量存在的獨立證據卻又不需要假設時空曲率、任何宇宙學近似或者天體物理學假設的獨特觀測實驗。 在本文中，我們首先用Sandage-Loeb方法檢測三種暗物質與暗能量的非引力相互作用，拓展全息Ricci暗能量模型，即考慮了三種相互作用項 的唯象形式，也就是 正比於Hubble膨脹率、暗組分的能量密度（即分別為 、 和 ），可以得出三種相互作用的解析解。我們發現在高紅移處，帶有哈勃參量的相互作用全息暗能量模型卻能夠與全息暗能量模型區分開；另外SL測試對於模型中Ωm0的變化不敏感，Ωm0的大小代表物質在整個組份中的含量，它的改變對檢測結果影響不大，也就是說它不是促使宇宙加速膨脹的主要原因。其次我們研究在精質暗能量模型中，將狀態方程從⋀CDM模型w=-1改變為離散函數時，宇宙組分隨紅移的變化情況，得出組分會隨著w的突越逐漸增加或減少的結論，並得出在w>0.4的範圍內變化明顯。最後我們將精質暗能量模型的解析解在紅移大於二小於五範圍內w為離散函數的結果帶入SL檢測，得到不同模型對於宇宙膨脹的敏感度不同，以及w在高紅移處對模型的影響更大的結果。其中 初始值最佳擬合範圍為Ω_m0＝〖0.287〗_(-0.027-0.036)^(+0.029+0.039)

The rapid development of space detection technology provides technical support for our study of dark energy, dark matter and other cosmological issues. In the process of exploring dark energy, all hypothetical models must be tested by experimental observations. The general step is to theorize the behavior of cosmological evolution and then test whether the observed data agrees with the model. The Sandage-Loeb (S-L) test serves as an experiment to measure the redshift of a distant object, which reflects the change in the expansion rate of the universe. Although the principle of this experiment is simple, it is capable of providing independent evidence on the existence of dark energy without making assumptions on space-time curvature, any cosmological approximations, or astrophysical postulations from unique observations. In this publication, we first used the Sandage-Loeb method to detect the non-gravitational interactions between the three types of dark matter and dark energy to expand the dark energy model of holographic Ricci. The phenomenological is proportional to Hubble’s expansion rate and energy density of the dark component ( , , and respectively), yielding the analytical solutions of the three interactions. We found out that the interacting holographic dark energy model with Hubble parameters can be distinguished from the holographic dark energy model. In addition, the S-L test is not sensitive to the change of Ωm0 in the model. The size of Ωm0 represents the quantity of the entire component. Since its change has little effect on the test results, it is not the main reason for the accelerated expansion of the universe. Next, we examined the change of the cosmic component in the Quintessence dark energy model. When the state equation is transformed from w = -1 into a discrete function, we observed a gradual increase or decrease of cosmic component based on the value of w. Hence, we identified that when w>0.4, the change is significant. Finally, we obtained the analytical results of the dark energy model in the range of redshift 2 ≤ z ≤ 5. Applying the redshift range and the discrete function to the S-L test, we concluded that the sensitivity of different models regarding universe expansion varies and that w has a greater impact on the model under high redshift. The initial value of the best fit range is Ω_m0＝〖0.287〗_(-0.027-0.036)^(+0.029+0.039).