标题： 非冷暗物质的迹象？ 具有恒定方程状态参数的流体暗物质的观测限制 显示英文标题

标题： Hints of noncold dark matter? Observational constraints on barotropic dark matter with a constant equation of state parameter

摘要： 这项研究探讨了称为$\Lambda w$DM 的宇宙学模型的潜力，其中宇宙常数起到暗能量的作用，而暗物质是等熵的，并且具有恒定的状态方程参数（$w_{\rm dm}$），以解决早期和晚期宇宙观测之间的$S_8$矛盾。 通过结合最新的宇宙学数据集——包括普朗克宇宙微波背景（CMB）、重子声学振荡（BAO）、Ia 型超新星（SNe Ia）、红移空间畸变（RSD）和弱引力透镜（WL）——我们对$\Lambda w$DM 与$\Lambda$CDM 进行了约束。 我们的分析显示，在结合 CMB、SDSS BAO、SNe Ia、RSD 和 WL 数据时，对非零$w_{\rm dm}=2.7^{+2.0}_{-1.9}\times10^{-7}$（在 95% 置信水平）有轻微偏好，而在结合 CMB、DESI Y1 BAO、SNe Ia、RSD 和 WL 数据时，对非零$w_{\rm dm} = 2.29^{+1.9}_{-2.0} \times 10^{-7}$（在 95% 置信水平）也有轻微偏好。 此外，我们发现，与$\Lambda$CDM 相比，$\Lambda w$DM 可以缓解从$>3\sigma$到$<1\sigma$的$S_8$紧张情况。 此外，我们发现，对于 CMB+SDSS+PP+RSD+WL 数据集，$\Lambda w$DM 模型相对于$\Lambda$CDM 模型更接近被积极偏好。 显示英文摘要

摘要： This study investigates the potential of a cosmological model termed $\Lambda w$DM, in which a cosmological constant play the role of dark energy and dark matter is barotropic and has a constant equation of state parameter ($w_{\rm dm}$), to address the $S_8$ tension between early- and late- universe observations. By incorporating the latest cosmological datasets -- including Planck Cosmic Microwave Background (CMB), Baryon Acoustic Oscillation (BAO), Ia supernovae (SNe Ia), Redshift Space Distortions (RSD), and weak lensing (WL) -- we constrain the $\Lambda w$DM compared to $\Lambda$CDM. Our analysis reveals a marginal preference for a non-zero $w_{\rm dm}=2.7^{+2.0}_{-1.9}\times10^{-7}$( at 95\% confidence level) when combining CMB, SDSS BAO, SNe Ia, RSD, and WL data, and a marginal preference for a non-zero $w_{\rm dm} = 2.29^{+1.9}_{-2.0} \times 10^{-7}$( at 95\% confidence level) when combining CMB, DESI Y1 BAO, SNe Ia, RSD, and WL data. In addition, we find that, compared to $\Lambda$CDM, $\Lambda w$DM can alleviate the $S_8$ tension from $>3\sigma$ to $<1\sigma$. Furthermore, we find that, for CMB+SDSS+PP+RSD+WL datasets, the $\Lambda w$DM model is close to being positively preferred over the $\Lambda$CDM model.