标题： 暗物质与暗能量相互作用项的重建利用Ia型超新星、BAO、CMB、H(z)和X射线气体质量分数 显示英文标题

标题： Reconstruction of the interaction term between dark matter and dark energy using SNe Ia, BAO, CMB, H(z) and X-ray gas mass fraction

摘要： 最近，在[1]中我们开发了一种参数化重建方法，用于一个均匀、各向同性和空间平坦的弗里德曼-罗伯逊-沃尔克（FRW）宇宙学模型，该模型充满了一种具有常数状态方程（EOS）参数的暗能量（DE）流体，并与暗物质（DM）相互作用。 该重建方法基于一般相互作用项和相关宇宙学变量的展开，以切比雪夫多项式形式表示，这些多项式形成一组完整的正交函数。 在本文中，我们仅通过前四个切比雪夫多项式展开相互作用函数，并假设三种模型来获得展开系数的最佳估计：(a) 一种状态方程参数w=-1的DE（一种相互作用的宇宙学Λ），(b) 一种状态方程参数w=常数且暗物质密度参数固定的DE，(c) 一种状态方程参数w=常数且自由常数暗物质密度参数待估计的DE。 在所有情况下，初步重建表明，在最佳情景下，近期过去存在穿越非相互作用线Q=0的可能性，即在1-sigma和2-sigma误差范围内，从早期时间的正值到晚期时间的负值。 这意味着在此重建中，早期时间存在从DE到DM的能量转移，而晚期时间存在从DM到DE的能量转移。 我们得出结论，这一事实表明在暗组分之间的普遍相互作用耦合中可能存在穿越行为。 最后，我们得出结论，在这种情景下，观测对相互作用的强度施加了很强的限制，因此其幅度无法解决巧合问题，或者至少不能显著缓解。 显示英文摘要

摘要： Recently, in [1] we developed a parametric reconstruction method to a homogeneous, isotropic and spatially flat Friedmann-Robertson-Walker (FRW) cosmological model filled of a fluid of dark energy (DE) with constant equation of state (EOS) parameter interacting with dark matter (DM). The reconstruction method is based on expansions of the general interaction term and the relevant cosmological variables in terms of Chebyshev polynomials which form a complete set orthonormal functions. In this article, we reconstruct the interaction function expanding it in terms of only the first four Chebyshev polynomials and obtain the best estimation for the coefficients of the expansion assuming three models: (a) a DE equation of the state parameter w=-1 (an interacting cosmological Lambda), (b) a DE equation of the state parameter w = constant with a dark matter density parameter fixed, (c) a DE equation of the state parameter w = constant with a free constant dark matter density parameter to be estimated. In all the cases, the preliminary reconstruction shows that in the best scenario there exist the possibility of a crossing of the noninteracting line Q=0 in the recent past within the 1-sigma and 2-sigma errors from positive values at early times to negative values at late times. This means that, in this reconstruction, there is an energy transfer from DE to DM at early times and an energy transfer from DM to DE at late times. We conclude that this fact is an indication of the possible existence of a crossing behavior in a general interaction coupling between dark components. Finally, we conclude that in this scenario, the observations put strong constraints on the strength of the interaction so that its magnitude can not solve the coincidence problem or at least alleviate significantly.