论文标题
万神殿+超新星中四极哈勃扩展的潜在签名
Potential signature of a quadrupolar Hubble expansion in Pantheon+ supernovae
论文作者
论文摘要
各向同性的假设 - 宇宙在大尺度上的所有方向上看起来都一样 - 是标准宇宙学模型的基础。该模型构成了迄今为止我们所有宇宙学知识的基础。因此，至关重要的是要经验测试其核心假设所具有的制度。由于晚期宇宙中的非线性结构，预计宇宙扩张中的各向异性会在小尺度上进行，但是，这些各向异性可能会影响我们的低降射观测值的程度仍有待充分的测试。在本文中，我们使用完全一般的相对论模拟来计算预期的局部各向异性扩展，并确定宇宙学参数中的主要多物是哈勃参数中的四极杆，而减速参数中的偶极子则是偶极子。我们在新的万神殿+超新星汇编中同时限制了这些多极。基准分析以特殊的速度校正在CMB的其余框架中进行。在哈勃流量样品中的红移基金会范围内，我们发现了$ \ sim2σ$偏离各向同性的偏差。我们将二次参数中四倍的特征值限制为$λ_1= 0.021 \ pm {0.011} $和$ {λ_2= 3.15 \ times 10^{ - 5}}} \ pm pm 0.012 $，并将$1σ$上限放在$ 2.88888888888888888888888888888888888888888888888888888888上。我们在减速参数中没有发现明显的偶极子，发现$ q _ {\ rm dip} = 4.5^{+1.9} _ { - 5.4} $的约束。但是，在CMB的其余框架没有校正的情况下，我们发现$ q_ {\ rm dip} = 9.6^{+4.0} _ { - 6.9} $，$>2σ$阳性振幅。我们还研究了这些各向异性对哈勃张力的影响。我们发现，在哈勃参数的单极管中，最大偏移$ 0.30 $ km s $^{ - 1} $ mpc $^{ - 1} $，得出结论，本地各向异性不太可能完全解释观察到的张力。
The assumption of isotropy -- that the Universe looks the same in all directions on large scales -- is fundamental to the standard cosmological model. This model forms the building blocks of essentially all of our cosmological knowledge to date. It is therefore critical to empirically test in which regimes its core assumptions hold. Anisotropies in the cosmic expansion are expected on small scales due to nonlinear structures in the late Universe, however, the extent to which these anisotropies might impact our low-redshift observations remains to be fully tested. In this paper, we use fully general relativistic simulations to calculate the expected local anisotropic expansion and identify the dominant multipoles in cosmological parameters to be the quadrupole in the Hubble parameter and the dipole in the deceleration parameter. We constrain these multipoles simultaneously in the new Pantheon+ supernova compilation. The fiducial analysis is done in the rest frame of the CMB with peculiar velocity corrections. Under the fiducial range of redshifts in the Hubble flow sample, we find a $\sim 2σ$ deviation from isotropy. We constrain the eigenvalues of the quadrupole in the Hubble parameter to be $λ_1 =0.021\pm{ 0.011}$ and $ {λ_2= 3.15\times 10^{-5}}\pm 0.012$ and place a $1σ$ upper limit on its amplitude of $2.88\%$. We find no significant dipole in the deceleration parameter, finding constraints of $q_{\rm dip} = 4.5^{+1.9}_{-5.4}$. However, in the rest frame of the CMB without corrections, we find $ q_{ \rm dip} = 9.6^{+4.0}_{-6.9}$, a $>2σ$ positive amplitude. We also investigate the impact of these anisotropies on the Hubble tension. We find a maximal shift of $0.30$ km s$^{-1}$ Mpc$^{-1}$ in the monopole of the Hubble parameter and conclude that local anisotropies are unlikely to fully explain the observed tension.
