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Related papers: A Test of Gravity with Pulsar Timing Arrays

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Pulsar-timing arrays (PTAs) are in the near future expected to detect a stochastic gravitational-wave background (SGWB) produced by a population of inspiralling super-massive black hole binaries. In this work, we consider a background that…

Cosmology and Nongalactic Astrophysics · Physics 2022-07-20 Gabriela Sato-Polito , Marc Kamionkowski

Globally, Pulsar Timing Array (PTA) experiments have revealed evidence supporting an existing gravitational wave background (GWB) signal in the PTA data set. Apart from acquiring more observations, the sensitivity of PTA experiments can be…

Instrumentation and Methods for Astrophysics · Physics 2025-04-03 El Mehdi Zahraoui , Patricio Maturana-Russel , Willem van Straten , Renate Meyer , Sergei Gulyaev

Pulsar Timing Array (PTA) experiments have entered a new era with evidence for a nanoHertz gravitational wave background (GWB). This review describes the physics of detection, detailing the noise models and cross-correlation techniques…

High Energy Astrophysical Phenomena · Physics 2026-04-01 C. M. F. Mingarelli , J. A. Casey-Clyde , Y. T. Chang , E. Eisenberg , F. Hutchison , N. Khusid , B. Larsen , A. Moran , F. Semenzato , L. Willson , Q. Zheng

Pulsar timing-array correlation measurements offer an exciting opportunity to test the nature of gravity in the cosmologically novel nanohertz gravitational wave regime. The stochastic gravitational wave background is assumed Gaussian and…

General Relativity and Quantum Cosmology · Physics 2022-11-23 Reginald Christian Bernardo , Kin-Wang Ng

We investigate the cross-correlation between astrometric and timing-residual observables for distant sources, such as pulsars and galaxies, and equivalent observables for nearby solar system bodies. Using the unified spin-weighted formalism…

General Relativity and Quantum Cosmology · Physics 2025-10-31 Elias Fink , Carlo Contaldi , Giorgio Mentasti

The Hellings-Downs (HD) correlation serves as the fundamental benchmark for detecting the gravitational-wave background (GWB) in pulsar timing arrays (PTAs) within General Relativity (GR). However, this canonical signature relies on the…

General Relativity and Quantum Cosmology · Physics 2026-02-17 Yan-Chen Bi , Yu-Mei Wu , Qing-Guo Huang

The recent astronomical milestone by the pulsar timing arrays (PTA) has revealed galactic-size gravitational waves (GW) in the form of a stochastic gravitational wave background (SGWB), correlating the radio pulses emitted by millisecond…

General Relativity and Quantum Cosmology · Physics 2024-11-08 Reginald Christian Bernardo , Kin-Wang Ng

We study the propagation of cosmological gravitational wave (GW) backgrounds from the early radiation era until the present day in modified theories of gravity. Comparing to general relativity (GR), we study the effects that modified…

General Relativity and Quantum Cosmology · Physics 2023-06-21 Yutong He , Alberto Roper Pol , Axel Brandenburg

Pulsar timing arrays act to detect gravitational waves by observing the small, correlated effect the waves have on pulse arrival times at Earth. This effect has conventionally been evaluated assuming the gravitational wave phasefronts are…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 Xihao Deng , Lee Samuel Finn

Pulsar Timing Array (PTA) observations hinted towards the existence of a stochastic gravitational wave background (SGWB) in the nHz frequency band. Still, the nature of the SGWB signal cannot be confidently inferred from current data, and…

Cosmology and Nongalactic Astrophysics · Physics 2024-04-04 Stanislav Babak , Mikel Falxa , Gabriele Franciolini , Mauro Pieroni

We have begun an exciting era for gravitational wave detection, as several world-leading experiments are breaching the threshold of anticipated signal strengths. Pulsar timing arrays (PTAs) are pan-Galactic gravitational wave detectors that…

Instrumentation and Methods for Astrophysics · Physics 2015-11-26 Sarah Burke-Spolaor

Recent pulsar timing array (PTA) analyses show evidence for a gravitational wave background (GWB) with angular correlations consistent with the Hellings-Downs curve. Anisotropies are a key discriminator of the origin of this GWB, as they…

Cosmology and Nongalactic Astrophysics · Physics 2025-09-01 Valerie Domcke , Gabriele Franciolini , Mauro Pieroni

Observing non-Gaussianity in the timing residuals of Pulsar Timing Arrays (PTAs) has recently attracted attention as a potential discriminator between astrophysical and cosmological origins of the observed Gravitational Wave (GW) signal. In…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-07 Chiara Cecchini , Jonas El Gammal , Gabriele Franciolini , Mauro Pieroni

Using public pulse time-of-arrival data from five pulsar timing arrays (PTAs), we search for a stationary, isotropic, and unpolarized nHz stochastic gravitational-wave background (SGWB). This analysis is more sensitive than previous…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-29 Wang-Wei Yu , Bruce Allen

Pulsar timing arrays (PTA) have the promise to detect gravitational waves (GWs) from sources which are in a unique frequency range of 10^-9 - 10^-6 Hz. This in turn also provides an opportunity to test the theory of general relativity in…

General Relativity and Quantum Cosmology · Physics 2020-10-07 Adrian Boîtier , Shubhanshu Tiwari , Lionel Philippoz , Philippe Jetzer

Searching for a modified dispersion relation is one of the general relativity tests performed by the LIGO-Virgo-KAGRA collaboration with each new cumulative Gravitational Wave Transient Catalog (GWTC). It considers classes of theories that…

General Relativity and Quantum Cosmology · Physics 2026-04-02 Tomasz Baka , Balázs Cirok , K. Haris , Johannes Noller , N. V. Krishnendu

The past decade has been a transformative period for pulsar timing arrays (PTAs) and their search for nanohertz gravitational waves (GWs). This progress has been driven by collective advances in instrumentation for pulsar timing…

High Energy Astrophysical Phenomena · Physics 2026-02-17 Kuo Liu , Siyuan Chen

Pulsar timing array (PTA) collaborations recently presented evidence for a gravitational-wave background (GWB) signal at nanohertz frequencies. In this paper, we introduce new refitting techniques for PTA data analysis that elevate related…

General Relativity and Quantum Cosmology · Physics 2025-07-01 David Esmyol , Antonio J. Iovino , Kai Schmitz

Pulsar timing array (PTA) experiments have recently provided strong evidence for the signal of the stochastic gravitational wave background (SGWB) in the nHz-frequency band. These experiments have shown a statistical preference for the…

Cosmology and Nongalactic Astrophysics · Physics 2024-12-18 Rubén Arjona , Savvas Nesseris , Sachiko Kuroyanagi

In Einstein's general relativity (GR), gravity is described by a massless spin-2 metric field, and the extension of GR to include a mass term for the graviton has profound implication for gravitation and cosmology. Besides the gravity…

General Relativity and Quantum Cosmology · Physics 2021-03-23 Lijing Shao