English
Related papers

Related papers: On the overlap reduction function of pulsar timing…

200 papers

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

Pulsar timing arrays (PTAs) are searching for nanohertz-frequency gravitational waves (GWs) through cross-correlation of pulse arrival times from a set of radio pulsars. PTAs have relied upon a frequency-shift formula of the pulse, where…

High Energy Astrophysical Phenomena · Physics 2024-07-03 Ryousuke Kubo , Kakeru Yamahira , Hideki Asada

Pulsar Timing Arrays (PTAs) have recently found strong evidence for low-frequency gravitational waves (GWs) in the nanohertz frequency regime. As GWs pass, they produce deviations in measured lengths and light-travel times. PTA experiments…

High Energy Astrophysical Phenomena · Physics 2025-05-05 Luke Zoltan Kelley

The pulsar timing array systems have reported a detection of a nanohertz-band stochastic gravitational wave background in our galaxy. It is of interest to use this observation to probe modified gravity and to forecast the sensitivity with…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-19 Jonathan Grée , Qiuyue Liang , Elisa G. M. Ferreira

There is growing interest in the overlap reduction function in pulsar timing array observations as a probe of modified gravity. However, current approximations to the Hellings-Downs curve for subluminal gravitational wave propagation, say…

General Relativity and Quantum Cosmology · Physics 2024-08-12 Guillem Domènech , Apostolos Tsabodimos

Pulsar timing arrays (PTAs) provide a way to detect gravitational waves (GWs) at nanohertz frequencies. To ensure the detection of GWs, observational data must exhibit the Hellings-Downs angular correlation. It is also known that PTAs can…

Cosmology and Nongalactic Astrophysics · Physics 2023-07-25 Hidetoshi Omiya , Kimihiro Nomura , Jiro Soda

State-of-the-art searches for gravitational waves (GWs) in pulsar timing array (PTA) datasets model the signal as an isotropic, Gaussian and stationary process described by a power-law. In practice, none of these properties are expected to…

High Energy Astrophysical Phenomena · Physics 2024-03-25 Serena Valtolina , Golam Shaifullah , Anuradha Samajdar , Alberto Sesana

For pulsar timing arrays (PTAs), the telltale signature of an isotropic stochastic background of gravitational waves is a pattern of pairwise interpulsar timing correlations approximately following the Hellings & Downs (HD) curve. Certain…

Instrumentation and Methods for Astrophysics · Physics 2024-11-01 Dustin R. Madison

Several pulsar-timing array (PTA) collaborations are finding tantalising hints for a stochastic gravitational wave background signal in the nano-Hertz regime. So far, though, no convincing evidence for the expected Hellings-Downs…

General Relativity and Quantum Cosmology · Physics 2022-04-20 Gianmassimo Tasinato

Several pulsar timing array (PTA) experiments such as NANOGrav and PPTA recently reported evidence of a gravitational wave (GW) background at nano-Hz frequency band. This signal can originate from scalar-induced gravitational waves (SIGW)…

Cosmology and Nongalactic Astrophysics · Physics 2025-04-04 Junsong Cang , Yu Gao , Yiming Liu , Sichun Sun

By regularly monitoring the most stable millisecond pulsars over many years, pulsar timing arrays (PTAs) are positioned to detect and study correlations in the timing behaviour of those pulsars. Gravitational waves (GWs) from supermassive…

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

In the nanohertz band, the spatial correlations in pulsar timing arrays (PTAs) produced by interfering gravitational waves (GWs) from multiple sources likely deviate from the traditional ones without interference under the assumption of an…

General Relativity and Quantum Cosmology · Physics 2025-10-01 Yu-Mei Wu , Yan-Chen Bi , Qing-Guo Huang

Pulsar timing arrays (PTAs) are used to search for long-wavelength gravitational waves (GWs) by monitoring a set of spin-stable millisecond pulsars. Most theoretical analyses assume that the relevant GW sources are much more distant from…

Astrophysics of Galaxies · Physics 2018-01-03 Dustin R. Madison , David F. Chernoff , James M. Cordes

Pulsar Timing Array (PTA) searches for nHz gravitational-wave backgrounds (GWBs) typically model time-correlated noise by assuming a diagonal covariance in Fourier space, neglecting inter-frequency correlations introduced by the finite…

Instrumentation and Methods for Astrophysics · Physics 2025-06-18 Marco Crisostomi , Rutger van Haasteren , Patrick M. Meyers , Michele Vallisneri

Pulsar timing arrays (PTAs) have recently provided compelling evidence for a stochastic gravitational wave background (SGWB) in the nanohertz frequency band, offering a unique window into fundamental physics. Here, we explore implications…

Cosmology and Nongalactic Astrophysics · Physics 2026-02-10 Mohammadreza Davari , Alireza Allahyari

We develop a full-covariance formalism for pulsar timing array(PTA) -- astrometry verlap reduction function (ORF) estimators and use it to forecast graviton-mass constraints from a nanohertz stochastic gravitational-wave background (SGWB).…

General Relativity and Quantum Cosmology · Physics 2026-04-30 Jing-Hong Han , Zhi-Chao Zhao

We answer frequently asked questions (FAQs) about the Hellings and Downs correlation curve -- the "smoking-gun" signature that pulsar timing arrays (PTAs) have detected gravitational waves (GWs). Many of these questions arise from…

General Relativity and Quantum Cosmology · Physics 2024-08-02 Joseph D. Romano , Bruce Allen

A low-frequency gravitational-wave background (GWB) from the cosmic merger history of supermassive black holes is expected to be detected in the next few years by pulsar timing arrays. A GWB induces distinctive correlations in the pulsar…

Instrumentation and Methods for Astrophysics · Physics 2018-10-30 Chiara M. F. Mingarelli , Angelo B. Mingarelli

The Hellings and Downs correlation curve describes the correlation of the timing residuals from pairs of pulsars as a function of their angular separation on the sky and is a smoking-gun signature for the detection of an isotropic…

General Relativity and Quantum Cosmology · Physics 2024-01-22 Alex Kehagias , Antonio Riotto