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arXiv 2005.02062astro-ph.COgr-qc
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暗能量性质的合理性

Soundness of Dark Energy properties

Eleonora Di Valentino, Stefano Gariazzo, Olga Mena, Sunny Vagnozzi

摘要:

Ia型超新星(SNeIa)被用作可分解的蜡烛,在宇宙加速的发现中起到了重要作用,通常归因于某种形式的暗能量(DE)。最近的研究提出了一个问题,即SNeIa的固有光度是否会随着红移而演化。虽然宇宙加速的证据对这种可能的系统是稳健的,但问题仍然是后者能在多大程度上影响负责宇宙加速的DE分量的推断性质。这就是我们在这项工作中要解决的问题。我们使用SNeIa距离模量测量从万神殿和JLA样品。我们认为,DE状态方程是一个自由参数的模型,无论是恒定的或随时间变化的,以及DE和暗物质相互作用的模型,最后一个模型不可知参数化的影响,由于修改后的重力(MG)。当SNeIa数据与宇宙微波背景(CMB)的温度和偏振各向异性测量相结合,我们发现强烈的退化之间的参数管理的SNeIa系统,DE参数,和哈勃常数$H_0$。这些简并显著扩大了DE参数的不确定性,在某些情况下导致中心值的${\cal O}(σ)$偏移。然而,包括低红移重子声学振荡和宇宙计时器测量,以及CMB透镜测量,大大改善了以前的限制,和唯一剩下的效果检查系统是一个$\lesssim 40\%$扩大DE参数的不确定性。相反,我们推导出的MG参数的约束基本上不受系统的影响。因此,我们确认整体健全的暗能量属性。

英文摘要:

Type Ia Supernovae (SNeIa) used as standardizable candles have been instrumental in the discovery of cosmic acceleration, usually attributed to some form of dark energy (DE). Recent studies have raised the issue of whether intrinsic SNeIa luminosities might evolve with redshift. While the evidence for cosmic acceleration is robust to this possible systematic, the question remains of how much the latter can affect the inferred properties of the DE component responsible for cosmic acceleration. This is the question we address in this work. We use SNeIa distance moduli measurements from the Pantheon and JLA samples. We consider models where the DE equation of state is a free parameter, either constant or time-varying, as well as models where DE and dark matter interact, and finally a model-agnostic parametrization of effects due to modified gravity (MG). When SNeIa data are combined with Cosmic Microwave Background (CMB) temperature and polarization anisotropy measurements, we find strong degeneracies between parameters governing the SNeIa systematics, the DE parameters, and the Hubble constant $H_0$. These degeneracies significantly broaden the DE parameter uncertainties, in some cases leading to ${\cal O}(σ)$ shifts in the central values. However, including low-redshift Baryon Acoustic Oscillation and Cosmic Chronometer measurements, as well as CMB lensing measurements, considerably improves the previous constraints, and the only remaining effect of the examined systematic is a $\lesssim 40\%$ broadening of the uncertainties on the DE parameters. The constraints we derive on the MG parameters are instead basically unaffected by the systematic in question. We therefore confirm the overall soundness of dark energy properties.

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