# The Odd-Parity Galaxy Bispectrum

## TL;DR

This paper explores the parity-odd component of the galaxy bispectrum, which is generated by galaxy velocities and could reveal new physics beyond standard cosmology, especially in modified gravity models.

## Contribution

It is the first study of the parity-odd galaxy bispectrum, highlighting its potential for testing gravity theories and probing new physics.

## Key findings

- Parity-odd bispectrum is generated by galaxy velocities.
- Signal is small in standard cosmology but larger in modified gravity.
- Offers a new method for testing gravity and cosmological models.

## Abstract

The galaxy bispectrum contains a wealth of information about the early universe, gravity, as well as astrophysics such as galaxy bias. In this paper, we study the parity-odd part of the galaxy bispectrum which is hitherto unexplored. In the standard cosmological model, the odd-parity bispectrum is generated by galaxy velocities through redshift-space distortions. While small in the case of General Relativity coupled with smooth dark energy, the signal could be larger in modified gravity scenarios. Thus, apart from being a very useful consistency test of measurements of galaxy clustering, the odd bispectrum offers a novel avenue for searching for new physics.