The dipole of the galaxy bispectrum. (6th May 2019)

• Record Type: Journal Article
• Authors: Clarkson, Chris; de Weerd, Eline M; Jolicoeur, Sheean; Maartens, Roy; Umeh, Obinna
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 486:Number 1(2019)
• Page Start: L101
• Page End: L104
• Publication Date: 2019-05-06
• Subjects: cosmology: theory -- large-scale structure of Universe; Astronomy -- Research -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnrasl/slz066
• Languages: English
• ISSNs: 1745-3933

Abstract

ABSTRACT: 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 on to our past light-cone. 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. The amplitude of the dipole can be more than 10 per cent of the monopole even on equality scales. Such a dipole is absent in the Newtonian approximation to the redshift space bispectrum, so it offers a clear signature of relativistic effects on cosmological scales in large-scale structure.