Tracking the Evolution of Supermassive Black Hole Binaries with Pulsar Terms
Abstract
Pulsar timing arrays will soon be able to resolve the loudest supermassive black hole binaries contributing to the stochastic gravitational wave background at nanohertz frequencies. While the few decades of observations are typically not enough to see these binaries evolve in frequency, the so-called pulsar terms offer a glimpse into the past and can help us map out the frequency evolution of these binaries over tens of thousands of years. Measuring this long-term frequency evolution can allow us to look for deviations from a vacuum binary evolution due to various environmental effects. We develop a Fisher-matrix approach to calculate how precisely the frequency can be tracked over time in this manner, and demonstrate its use on a realistic near-future pulsar timing array with a 30-year baseline. We find that the environmental effects predicted by 2-dimensional hydrodynamic simulations of circumbinary disks are unlikely to be detectable in the circular binaries we considered, however, in some cases they might result in biased chirp mass recovery if ignored. We also demonstrate how this approach allows one to test the orbital evolution predicted by general relativity in a purely gravitational-wave driven inspiral, and to put upper limits on additional generic environmental effects described by a power-law hardening model.
Related
- Parameter Estimation for Eccentric Supermassive Black Hole Binaries with Pulsar Timing Arrays
- Electromagnetic Emission and Orbital Evolution of Eccentric Supermassive Black Hole Binaries in Retrograde Disks
- Granular mass perturbations on the pulsar - supermassive black hole system
- Hierarchical Inference of the Supermassive Black Hole Binary Merger Rates from Joint Searches using Pulsar Timing Arrays
- Odds Estimation for Supermassive Black Hole Binaries in Local Core Galaxies
BibTeX
@misc{becsy2026tracking,
title = {{Tracking the Evolution of Supermassive Black Hole Binaries with Pulsar Terms}},
author = {Bence Bécsy and Magdalena Siwek},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.32736},
eprint = {2610.32736},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.32736},
}
RIS
TY - UNPB
TI - Tracking the Evolution of Supermassive Black Hole Binaries with Pulsar Terms
AU - Bence Bécsy
AU - Magdalena Siwek
PY - 2026
DA - 2026/10/23
PB - arXiv
DO - 10.48550/arxiv.2610.32736
UR - https://arxiv.org/abs/2610.32736
AB - Pulsar timing arrays will soon be able to resolve the loudest supermassive black hole binaries contributing to the stochastic gravitational wave background at nanohertz frequencies. While the few decades of observations are typically not enough to see these binaries evolve in frequency, the so-called pulsar terms offer a glimpse into the past and can help us map out the frequency evolution of these binaries over tens of thousands of years. Measuring this long-term frequency evolution can allow us to look for deviations from a vacuum binary evolution due to various environmental effects. We develop a Fisher-matrix approach to calculate how precisely the frequency can be tracked over time in this manner, and demonstrate its use on a realistic near-future pulsar timing array with a 30-year baseline. We find that the environmental effects predicted by 2-dimensional hydrodynamic simulations of circumbinary disks are unlikely to be detectable in the circular binaries we considered, however, in some cases they might result in biased chirp mass recovery if ignored. We also demonstrate how this approach allows one to test the orbital evolution predicted by general relativity in a purely gravitational-wave driven inspiral, and to put upper limits on additional generic environmental effects described by a power-law hardening model.
ER -