Local primordial non-Gaussianity in the relativistic galaxy bispectrum
arXiv:2011.13660 · doi:10.1088/1475-7516/2021/04/013
Abstract
Next-generation galaxy and 21cm intensity mapping surveys will rely on a combination of the power spectrum and bispectrum for high-precision measurements of primordial non-Gaussianity. In turn, these measurements will allow us to distinguish between various models of inflation. However, precision observations require theoretical precision at least at the same level. We extend the theoretical understanding of the galaxy bispectrum by incorporating a consistent general relativistic model of galaxy bias at second order, in the presence of local primordial non-Gaussianity. The influence of primordial non-Gaussianity on the bispectrum extends beyond the galaxy bias and the dark matter density, due to redshift-space effects. The standard redshift-space distortions at first and second order produce a well-known primordial non-Gaussian imprint on the bispectrum. Relativistic corrections to redshift-space distortions generate new contributions to this primordial non-Gaussian signal, arising from: (1)~a coupling of first-order scale-dependent bias with first-order relativistic observational effects, and (2)~linearly evolved non-Gaussianity in the second-order velocity and metric potentials which appear in relativistic observational effects. Our analysis allows for a consistent separation of the relativistic `contamination' from the primordial signal, in order to avoid biasing the measurements by using an incorrect theoretical model. We show that the bias from using a Newtonian analysis of the squeezed bispectrum could be $Δ\fnl\sim 5$ for a Stage IV H survey.
Version accepted by JCAP (JCAP_030P_1220) + 18 pages + 4 figures + appendices + references
References in corpus (18)
- The imprints of primordial non-gaussianities on large-scale structure: scale dependent bias and abundance of virialized objects
- New Perspective on Galaxy Clustering as a Cosmological Probe: General Relativistic Effects
- Cosmology and the Bispectrum
- The bispectrum of galaxies from high-redshift galaxy surveys: primordial non-Gaussianity and non-linear galaxy bias
- Testing General Relativity with 21 cm intensity mapping
- Beyond the Linear-Order Relativistic Effect in Galaxy Clustering: Second-Order Gauge-Invariant Formalism
- Galaxy number counts to second order and their bispectrum
- Einstein's legacy in galaxy surveys
- Information Content of the Angular Multipoles of Redshift-Space Galaxy Bispectrum
- Quantifying the Redshift Space Distortion of the Bispectrum I: Primordial Non-Gaussianity
- Non-Gaussianities due to Relativistic Corrections to the Observed Galaxy Bispectrum
- A general relativistic signature in the galaxy bispectrum: the local effects of observing on the lightcone
- Beware of commonly used approximations II: estimating systematic biases in the best-fit parameters
- Disantangling the effects of Doppler velocity and primordial non-Gaussianity in galaxy power spectra
- Probing the primordial Universe with MeerKAT and DES
- Unveiling the nature of the unidentified gamma-ray sources VI: gamma-ray blazar candidates in the WISH survey and their radio properties
- Non-local bias in the halo bispectrum with primordial non-Gaussianity
- General relativistic effects in the galaxy bias at second order