Cosmological constraints and phenomenology of a beyond-Horndeski model
Cosmological constraints and phenomenology of a beyond-Horndeski model
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DOI：
10.1103/physrevd.100.063509
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发表时间：
2019-05
影响因子：
5
通讯作者：
S. Peirone;G. Benevento;N. Frusciante;S. Tsujikawa
中科院分区：
文献类型：
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作者：
S. Peirone;G. Benevento;N. Frusciante;S. Tsujikawa
我们在Gleyzes-Langlois-Piazza-Vernizzi理论的框架下研究了一个特定暗能量模型的观测约束，将伽利略鬼凝聚（GGC）扩展到Horndeski理论之外的领域。在这个模型中，我们展示了普朗克宇宙微波背景（CMB）数据，结合重子声学振荡、Ia型超新星和红移空间畸变的数据集，给出了今天的beyond-Horndeski （BH）参数αH的紧密上界|α(0)H|≤O（10−6）。这主要是由于宇宙背景的早期变化和αH在暗能量密度中占主导地位引起的扰动引起的CMB声峰的移动。与Λ冷暗物质（ΛCDM）模型相比，由于立方伽利略的存在，我们的黑洞模型抑制了CMB温度各向异性的大尺度综合sachs - wolfe尾巴，并且由于背景演化的不同，它修改了小尺度CMB功率谱。根据χ2统计，我们发现所考虑的BH模型比ΛCDM更适合数据，但偏差信息准则（DIC）略偏向后者。考虑到我们的αH=0的黑洞模型（即GGC模型）比ΛCDM更受DIC的青睐，在目前的观测中没有特别的迹象表明它偏离了Horndeski理论。
We study observational constraints on a specific dark energy model in the framework of Gleyzes-Langlois-Piazza-Vernizzi theories, which extends the Galileon ghost condensate (GGC) to the domain of beyond Horndeski theories. In this model, we show that the Planck cosmic microwave background (CMB) data, combined with datasets of baryon acoustic oscillations, supernovae type Ia, and redshift-space distortions, give the tight upper bound |α(0)H|≤O(10−6) on today’s beyond-Horndeski (BH) parameter αH. This is mostly attributed to the shift of CMB acoustic peaks induced by the early-time changes of cosmological background and perturbations arising from the dominance of αH in the dark energy density. In comparison to the Λ cold dark matter (ΛCDM) model, our BH model suppresses the large-scale integrated-Sachs-Wolfe tail of CMB temperature anisotropies due to the existence of cubic Galileons, and it modifies the small-scale CMB power spectrum because of the different background evolution. We find that the BH model considered fits the data better than ΛCDM according to the χ2 statistics, yet the deviance information criterion (DIC) slightly favors the latter. Given the fact that our BH model with αH=0 (i.e., the GGC model) is favored over ΛCDM even by the DIC, there are no particular signatures for the departure from Horndeski theories in current observations.