The dipole of the galaxy bispectrum

Understand

The bispectrum will play an important role in future galaxy surveys.

• On large scales it is a key probe for measuring primordial non-Gaussianity which can help differentiate between different inflationary models and other theories of the early universe.
• On these scales a variety of relativistic effects come into play once the galaxy number-count fluctuation is projected onto our past lightcone.
• We show for the first time that the leading relativistic correction from these distortions in the galaxy bispectrum generates a significant dipole, mainly from relativistic redshift space distortions.