gwaxion

This is a package to facilitate computations related to gravitational waves from ultralight-boson condensates around black holes. The code was primarilty developed in writing arXiv:1810.03812, but it is of broad applicability.

The primary objects in this package are:

• BlackHoleBoson
• BosonCloud

Their use, as well as other features, is demonstrated in a set of Jupyter notebooks in the examples/ directory.

Computations of boson cloud evolution and gravitational-wave emission rely on results from arXiv:1411.0686, arXiv:1706.06311 and made use of the data and code available in gw_superradiance.

Installation

pip install gwaxion

Usage

Here is a barebones example to get some properties of a given black-hole--boson system, for a BH with mass M = 50 Msun and dimensionless spin chi = 0.9, and a boson with mass such that alpha = 0.2.

import gwaxion

# create a black-hole--boson object (scalar boson by default)
bhb = gwaxion.BlackHoleBoson.from_parameters(m_bh=50, chi_bh=0.9, alpha=0.2)

# get the fastest-growing boson level
# (l, m, nr, growth rate in Hz)
bhb.max_growth_rate()
# > (1, 1, 0, 4.175501554995195e-06)

# get the mass of the corresponding cloud after superradiant growth
# as a fraction of the original BH mass
cloud = bhb.best_cloud()
cloud.mass / cloud.bhb_initial.bh.mass
# > 0.066

For more examples see the examples/ directory.

Credit

This code was developed by Maximiliano Isi with important contributions by Richard Brito.

If you make use of this code for your own publications, please refer to the Zenodo DOI (see blue badge above) and cite:

@article{Isi:2018pzk,
    author = "Isi, Maximiliano and Sun, Ling and Brito, Richard and Melatos, Andrew",
    title = "{Directed searches for gravitational waves from ultralight bosons}",
    eprint = "1810.03812",
    archivePrefix = "arXiv",
    primaryClass = "gr-qc",
    reportNumber = "LIGO-P1800270",
    doi = "10.1103/PhysRevD.99.084042",
    journal = "Phys. Rev. D",
    volume = "99",
    number = "8",
    pages = "084042",
    year = "2019",
    note = "[Erratum: Phys.Rev.D 102, 049901 (2020)]"
}

(This might be replaced by a dedicated publication at a later date.)