Foglieni Matteo, Pantiri Mattia, Di Dio Enea, Castorina Emanuele
Leibniz Supercomputing Centre (LRZ), Boltzmannstraße 1, 85748 Garching bei München, Germany.
Dipartimento di Fisica "Aldo Pontremoli", Universita' degli Studi di Milano, Via Celoria 16, 20133 Milan, Italy.
Phys Rev Lett. 2023 Sep 15;131(11):111201. doi: 10.1103/PhysRevLett.131.111201.
The large scale limit of the galaxy power spectrum provides a unique window into the early Universe through a possible detection of scale dependent bias produced by primordial non Gaussianities. On such large scales, relativistic effects could become important and be confused for a primordial signal. In this Letter we provide the first consistent estimate of such effects in the observed galaxy power spectrum, and discuss their possible degeneracy with local primordial non Gaussianities. We also clarify the physical differences between the two signatures, as revealed by their different sensitivity to the large scale gravitational potential. Our results indicate that, while relativistic effects could easily account for 10% of the observed power spectrum, the subset of those with a similar scale dependence to a primordial signal can be safely ignored for current galaxy surveys, but it will become relevant for future observational programs.
星系功率谱的大尺度极限通过可能探测到由原初非高斯性产生的尺度依赖偏差，为早期宇宙提供了一个独特的窗口。在如此大的尺度上，相对论效应可能变得重要，并与原初信号混淆。在本快报中，我们首次对观测到的星系功率谱中的此类效应进行了一致估计，并讨论了它们与局域原初非高斯性可能存在的简并性。我们还阐明了这两种特征之间的物理差异，这体现在它们对大尺度引力势的不同敏感性上。我们的结果表明，虽然相对论效应很容易解释观测到的功率谱的10%，但对于当前的星系巡天，那些与原初信号具有相似尺度依赖性的效应子集可以安全地忽略，但对于未来的观测计划将变得至关重要。
