宇宙透明性：重子声学特征和Ia型超新星的检验
Cosmic transparency: A test with the baryon acoustic feature and type Ia supernovae
摘要：
光子的相空间密度守恒加上洛伦兹不变性要求宇宙学光度距离比角直径距离大$(1+z)^2$倍，其中$z$是红移。因为这是一个基本的对称性，这个预测-有时被称为“埃瑟林顿关系”或“托尔曼测试”-是独立的世界模型，甚至假设的同质性和各向同性。然而，它依赖于洛伦兹不变性和透明性。透明度可能会受到星系间尘埃或光子与暗区之间相互作用的影响。重子声学特征和Ia型超新星膨胀历史的测量对角直径和光度距离的敏感性不同，因此可以结合使用来限制宇宙的透明度。目前，该比较仅将可见波长处的光学深度从红移0.20至0.35的$Δτ$变化限制为95%置信度下的$Δτ< 0.13$。在具有恒定固有横截面$σ$的散射体的恒定共动数密度$n$的模型中，该极限意味着$n σ< 2\times10^{-4} h \Mpc^{-1}$。这些极限弱依赖于宇宙学世界模型。在接下来的几年里，极限可能会扩展到红移$z\approx2.5$，并改进到$n σ<1.1 \times10^{-5} h \Mpc^{-1}$。宇宙方差最终将限制在$n σ\sim 4\times10^{-7} h \Mpc^{-1}$水平使用BAF的任何测试的灵敏度。提供了与其他透明度测量方法的比较;在可见光中没有其他测量方法是不受天体物理学假设的影响的。
英文摘要：
Conservation of the phase-space density of photons plus Lorentz invariance requires that the cosmological luminosity distance be larger than the angular diameter distance by a factor of $(1+z)^2$, where $z$ is the redshift. Because this is a fundamental symmetry, this prediction--known sometimes as the "Etherington relation" or the "Tolman test"--is independent of world model, or even the assumptions of homogeneity and isotropy. It depends, however, on Lorentz invariance and transparency. Transparency can be affected by intergalactic dust or interactions between photons and the dark sector. Baryon acoustic feature and type Ia supernovae measures of the expansion history are differently sensitive to the angular diameter and luminosity distances and can therefore be used in conjunction to limit cosmic transparency. At the present day, the comparison only limits the change $Δτ$ in the optical depth from redshift 0.20 to 0.35 at visible wavelengths to $Δτ< 0.13$ at 95% confidence. In a model with a constant comoving number density $n$ of scatterers of constant proper cross-section $σ$, this limit implies $n σ< 2\times10^{-4} h \Mpc^{-1}$. These limits depend weakly on the cosmological world model. Within the next few years, the limits could extend to redshifts $z\approx2.5$ and improve to $n σ<1.1 \times10^{-5} h \Mpc^{-1}$. Cosmic variance will eventually limit the sensitivity of any test using the BAF at the $n σ\sim 4\times10^{-7} h \Mpc^{-1}$ level. Comparison with other measures of the transparency is provided; no other measure in the visible is as free of astrophysical assumptions.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
