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 ${\cal O}(\sigma)$ 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.

中文翻译：

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暗能量属性的稳健性

用作标准化烛光的 Ia 型超新星 (SNeIa) 有助于发现宇宙加速，通常归因于某种形式的暗能量 (DE)。最近的研究提出了本征 SNeIa 光度是否会随着红移而演变的问题。虽然宇宙加速的证据对这个可能的系统来说是可靠的，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 分量的推断特性。这是我们在这项工作中解决的问题。我们使用来自 Pantheon 和 JLA 样本的 SNeIa 距离模量测量值。我们考虑 DE 状态方程是一个自由参数（常数或时变）的模型，以及 DE 和暗物质相互作用的模型，最后，由于修正重力 (MG) 的影响的模型不可知参数化。当 SNeIa 数据与宇宙微波背景 (CMB) 温度和极化各向异性测量值相结合时，我们发现控制 SNeIa 系统学的参数、DE 参数和哈勃常数 $H_0$ 之间存在强烈的简并性。这些简并显着扩大了 DE 参数的不确定性，在某些情况下会导致中心值的 ${\cal O}(\sigma)$ 偏移。然而，包括低红移重子声学振荡和宇宙天文钟测量，以及 CMB 透镜测量，大大改善了以前的限制，并且检查系统的唯一剩余影响是 $\lesssim 40\%$ DE 参数。相反，我们对 MG 参数得出的约束基本上不受相关系统的影响。因此，我们确认了暗能量特性的整体稳健性。