Large Scale Limit of the Observed Galaxy Power Spectrum

Understand

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.