Speaker
Description
Upcoming galaxy surveys aim to map the universe with unprecedented precision, depth and sky coverage. The galaxy bispectrum is a prime source of information as it allows us to probe primordial non-Gaussianity (PNG), a key factor in differentiating various models of inflation. On the scales where local PNG is strongest, Doppler and other relativistic effects become important and need to be included. In this work, we investigate the detectability of relativistic and local PNG contributions in the galaxy bispectrum. We compute the signal-to-noise ratio for the detection of the bispectrum including such effects. Furthermore, we perform information matrix forecasts on the local PNG parameter fNL and on the parametrised amplitudes of the relativistic corrections. Finally, we quantify the bias on fNL from neglecting relativistic effects. Our results show that detections of both first- and second-order relativistic effects are promising with forthcoming spectroscopic survey specifications – and are largely unaffected by the uncertainty in fNL. Conversely, we show for the first time that neglecting relativistic corrections in the galaxy bispectrum can lead to almost 3σ bias on the detected value of fNL, highlighting the importance of including relativistic effects in our modelling.
