We present version 2.1 of the public code {\sc precession}, a Python module for studying the post-Newtonian dynamics of precessing black hole binaries. In this release, we extend the code to handle eccentric orbits. This extension leverages the existing numerical infrastructure wherever possible, introducing a semi-automatic method to adapt circular-orbit functions to the eccentric case via a Python decorator. Additional new features include orbit- and precession-averaged evolutionary equations for the eccentricity, as well as revised expressions to convert between post-Newtonian separation and gravitational-wave emission frequency.
@article{arxiv.2508.21125,
title = {PRECESSION 2.1: black-hole binary spin precession on eccentric orbits},
author = {Giulia Fumagalli and Davide Gerosa and Nicholas Loutrel},
journal= {arXiv preprint arXiv:2508.21125},
year = {2026}
}
Comments
5 pages, 1 figure; Proceeding of the GR24-Amaldi16 conference