UV luminosity functions provide a wealth of information on the physics of galaxy formation in the early Universe. Given that this probe indirectly tracks the evolution of the mass function of dark matter halos, it has the potential to constrain alternative theories of structure formation. One of such scenarios is the existence of primordial non-Gaussianity at scales beyond those probed by observations of the Cosmic Microwave Background. Through its impact on the halo mass function, such small-scale non-Gaussianity would alter the abundance of galaxies at high redshifts. In this work we present an application of UV luminosity functions as measured by the Hubble Space Telescope to constrain the non-Gaussianity parameter $f_\mathrm{NL}$ for wavenumbers above a cut-off scale $k_{\rm cut}$. After marginalizing over the unknown astrophysical parameters and accounting for potential systematic errors, we arrive at a $2\sigma$ bound of $f_{\rm NL}=71^{+426}_{-237}$ for a cut-off scale $k_{\rm cut}=0.1\,\mathrm{Mpc}^{-1}$ in the bispectrum of the primordial gravitational potential. Moreover, we perform forecasts for the James Webb Space Telescope, as well as future global-signal and interferometric 21-cm experiments, finding an expected improvement of a factor $3-4$ upon the current bound.

中文翻译：

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来自紫外线星系光度函数的小尺度非高斯性的第一个约束

紫外光度函数提供了大量关于早期宇宙星系形成物理学的信息。鉴于该探测器间接跟踪暗物质晕质量函数的演变，它有可能限制结构形成的替代理论。其中一种情况是在超出宇宙微波背景观测所探测到的尺度上存在原始非高斯性。通过对晕质量函数的影响，这种小尺度的非高斯性将改变高红移星系的丰度。在这项工作中，我们提出了一种应用由哈勃太空望远镜测量的 UV 光度函数，以约束高于截止尺度 $k_{\rm cut}$ 的波数的非高斯参数 $f_\mathrm{NL}$。在对未知的天体物理参数进行边缘化并考虑潜在的系统误差后，我们得出了一个 $f_{\rm NL}=71^{+426}_{-237}$ 的 $2\sigma$ 界限作为截止尺度$k_{\rm cut}=0.1\,\mathrm{Mpc}^{-1}$ 在原始引力势双谱中。此外，我们对詹姆斯·韦伯太空望远镜以及未来的全球信号和干涉测量 21 厘米实验进行了预测，发现在当前界限的基础上，预期提高了 3-4 美元。