This code is a complement to the bilby package and enables one to perform relative binning in bilby. The code can use waveform with higher order modes and precession to perform parameter estimation. The code is also able to peform joint parameter estimation for strongly lensed events.

Relative binning is a method to perform bayesian parameter inference for gravitational waves in a faster way. It has been developped in Zackay et al (2018), Dai et al (2018), and Dai et al, repo. Additionally, attempts have been made to develop relative binning for higher-order modes waveforms (see Leslie et al (2021)).

In this repo, we use the ideas from Zackay et al (2018) and convert them into a bilby compatible format, making it easier to use.

The codebase to perform PE with IMRPhenomXPHM waveform is based on the work by Narola et al (2023)

If you use this code for your work, please give due credits by citating the methodology papers:

@article{Zackay:2018qdy, author = "Zackay, Barak and Dai, Liang and Venumadhav, Tejaswi", title = "{Relative Binning and Fast Likelihood Evaluation for Gravitational Wave Parameter Estimation}", eprint = "1806.08792", archivePrefix = "arXiv", primaryClass = "astro-ph.IM", month = "6", year = "2018" }

@article{Dai:2018dca, author = "Dai, Liang and Venumadhav, Tejaswi and Zackay, Barak", title = "{Parameter Estimation for GW170817 using Relative Binning}", eprint = "1806.08793", archivePrefix = "arXiv", primaryClass = "gr-qc", month = "6", year = "2018" }

(for higher order modes:

@article{Leslie:2021ssu, author = "Leslie, Nathaniel and Dai, Liang and Pratten, Geraint", title = "{Mode-by-mode relative binning: Fast likelihood estimation for gravitational waveforms with spin-orbit precession and multiple harmonics}", eprint = "2109.09872", archivePrefix = "arXiv", primaryClass = "astro-ph.IM", doi = "10.1103/PhysRevD.104.123030", journal = "Phys. Rev. D", volume = "104", number = "12", pages = "123030", year = "2021" }

@article{Narola:2023men, author = "Narola, Harsh and Janquart, Justin and Meijer, Quirijn and Haris, K. and Van Den Broeck, Chris", title = "{Relative binning for complete gravitational-wave parameter estimation with higher-order modes and precession, and applications to lensing and third-generation detectors}", eprint = "2308.12140", archivePrefix = "arXiv", primaryClass = "gr-qc", month = "8", year = "2023" }

)

And also citing this repository: @misc{janquart:2022, author = "Janquart, Justin", "Harsh Narola", title="{RelativeBilbying: a package for relative binning with bilby}", year={2022}, howpublished={\url{https://github.com/lemnis12/relativebilbying}} }

a) Using PyPI, you can just run pip install relativebilbying

b) using this repo:

• clone the repository
• run pip install .

• relativebilbying: folder with the likelihoods to perfrom relative binning in bilby
• example: folder with example runs for injection on how to use these scripts.
  1. single_event_pe.py: Start a PE runs on a GW150914 like injection with XPHM waveform
  2. lensed_event_joint_pe.py: Start a joint PE run on a pair of two images generated by strong lensing.