Probing Kinematic Anisotropies in the Stochastic Gravitational Wave Background with the SKA

arXiv:2606.25845 · astro-ph.CO, gr-qc · Submitted 2026-06-24 · Read on arXiv

N. M. J. Cruz, Ameek Malhotra, Gianmassimo Tasinato, Ivonne Zavala

astro-ph.CO, gr-qc

Submitted: 2026-06-24

Comments: Published in Advancing Astrophysics with the SKA II (AASKAII), 2026 (arXiv:2606.20366). Report-no:AASKAII/Cruz01

License: http://creativecommons.org/licenses/by-nc-sa/4.0/

The gist: Pulsar Timing Arrays (PTAs) and astrometric surveys provide complementary probes of the nanohertz stochastic gravitational-wave background (SGWB).

Terminology

Anisotropy — 6× in this paper · explained in 3 episodes
pulsar timing arrays — 5× in this paper · explained in 2 episodes
Square Kilometre Array Observatory — 4× in this paper
Accuracy — 1× in this paper · explained in 1 episode
Alignment — 1× in this paper · explained in 1 episode
Benchmark — 1× in this paper · explained in 2 episodes
Clustering — 1× in this paper · explained in 2 episodes
Consistency — 1× in this paper · explained in 3 episodes
Fisher matrix formalism — 1× in this paper · explained in 2 episodes
Frequency Dependence — 1× in this paper · explained in 2 episodes
Phase Transitions — 1× in this paper · explained in 2 episodes
Symmetry Breaking — 1× in this paper · explained in 3 episodes
Trace — 1× in this paper · explained in 2 episodes

Abstract

Pulsar Timing Arrays (PTAs) and astrometric surveys provide complementary probes of the nanohertz stochastic gravitational-wave background (SGWB). A primary target is the kinematic dipole induced by the Solar System's motion, whose detection would confirm the SGWB's cosmological origin. We forecast the sensitivity of the Square Kilometre Array Observatory (SKAO) using optimal estimators and Fisher techniques, considering both the baseline AA4 configuration and an optimistic 1000 pulsar scenario, including the potential gain from combining with Gaia-like astrometry. While SKAO will substantially improve constraints on SGWB anisotropies, even joint analyses remain below the sensitivity required to detect the kinematic dipole, motivating new observational and analysis strategies to fully exploit this signal.

Probing Kinematic Anisotropies in the Stochastic Gravitational Wave Background with the SKA

Terminology

Abstract

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