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Large Scale Limit of the Observed Galaxy Power Spectrum
Matteo Foglieni1,2, Mattia Pantiri2, Enea Di Dio3
1Leibniz Supercomputing Centre (LRZ), Boltzmannstraße 1, 85748 Garching bei München, Germany.
Physical Review Letters
|September 29, 2023
Summary
Relativistic effects in the galaxy power spectrum can mimic primordial signals. While significant, these effects are distinguishable and ignorable for current surveys, but crucial for future ones.
Area of Science:
- Cosmology
- Astrophysics
- Galaxy Formation and Evolution
Background:
- The galaxy power spectrum offers insights into the early Universe, particularly through scale-dependent bias from primordial non-Gaussianities.
- Relativistic effects on large scales can be mistaken for primordial signals, complicating interpretations of cosmological data.
Purpose of the Study:
- To provide the first consistent estimate of relativistic effects on the observed galaxy power spectrum.
- To analyze the potential degeneracy between relativistic effects and local primordial non-Gaussianities.
- To differentiate the physical signatures of relativistic effects and primordial non-Gaussianities.
Main Methods:
- Consistent estimation of relativistic effects within the galaxy power spectrum.
- Analysis of the scale-dependent bias introduced by these effects.
- Comparison of relativistic effects with primordial non-Gaussianities' signatures.
Main Results:
- Relativistic effects can account for up to 10% of the observed galaxy power spectrum.
- A subset of relativistic effects exhibits scale dependence similar to primordial signals.
- Relativistic effects and primordial non-Gaussianities show different sensitivities to the large-scale gravitational potential.
Conclusions:
- Relativistic effects can be safely ignored for current galaxy surveys due to their distinct signatures.
- These effects will become increasingly relevant for future observational programs aiming for higher precision.
- Distinguishing relativistic effects is crucial for accurately interpreting the early Universe through the galaxy power spectrum.
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