Astrometry meets Pulsar Timing Arrays: Synergies for Gravitational Wave Detection

Fuente: arXiv
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Main Authors: Cruz, N. M. Jiménez, Malhotra, Ameek, Tasinato, Gianmassimo, Zavala, Ivonne
Format: Preprint
Published: 2024
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author Cruz, N. M. Jiménez
Malhotra, Ameek
Tasinato, Gianmassimo
Zavala, Ivonne
author_facet Cruz, N. M. Jiménez
Malhotra, Ameek
Tasinato, Gianmassimo
Zavala, Ivonne
contents High-precision astrometry offers a promising approach to detect low-frequency gravitational waves, complementing pulsar timing array (PTA) observations. We explore the response of astrometric measurements to a stochastic gravitational wave background (SGWB) in synergy with PTA data. Analytical, covariant expressions for this response are derived, accounting for the presence of a possible dipolar anisotropy in the SGWB. We identify the optimal estimator for extracting SGWB information from astrometric observations and examine how sensitivity to SGWB properties varies with the sky positions of stars and pulsars. Using representative examples of current PTA capabilities and near-future astrometric sensitivity, we demonstrate that cross-correlating astrometric and PTA data can improve constraints on SGWB properties, compared to PTA data alone. The improvement is quantified through Fisher forecasts for the SGWB amplitude, spectral tilt, and dipolar anisotropy amplitude. In the future, such joint constraints could play a crucial role in identifying the origin of SGWB signals detected by PTAs.
format Preprint
id arxiv_https___arxiv_org_abs_2412_14010
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Astrometry meets Pulsar Timing Arrays: Synergies for Gravitational Wave Detection
Cruz, N. M. Jiménez
Malhotra, Ameek
Tasinato, Gianmassimo
Zavala, Ivonne
Cosmology and Nongalactic Astrophysics
General Relativity and Quantum Cosmology
High Energy Physics - Theory
High-precision astrometry offers a promising approach to detect low-frequency gravitational waves, complementing pulsar timing array (PTA) observations. We explore the response of astrometric measurements to a stochastic gravitational wave background (SGWB) in synergy with PTA data. Analytical, covariant expressions for this response are derived, accounting for the presence of a possible dipolar anisotropy in the SGWB. We identify the optimal estimator for extracting SGWB information from astrometric observations and examine how sensitivity to SGWB properties varies with the sky positions of stars and pulsars. Using representative examples of current PTA capabilities and near-future astrometric sensitivity, we demonstrate that cross-correlating astrometric and PTA data can improve constraints on SGWB properties, compared to PTA data alone. The improvement is quantified through Fisher forecasts for the SGWB amplitude, spectral tilt, and dipolar anisotropy amplitude. In the future, such joint constraints could play a crucial role in identifying the origin of SGWB signals detected by PTAs.
title Astrometry meets Pulsar Timing Arrays: Synergies for Gravitational Wave Detection
topic Cosmology and Nongalactic Astrophysics
General Relativity and Quantum Cosmology
High Energy Physics - Theory
url https://arxiv.org/abs/2412.14010