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Related papers: Beyond the Hellings-Downs curve: Non-Einsteinian g…

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Pulsar timing arrays (PTAs), aimed at detecting gravitational waves (GWs) in the $1\sim 100$ nHz range, have recently made significant strides. Compelling evidence has emerged for a common spectrum signal spatially correlated among pulsars,…

Cosmology and Nongalactic Astrophysics · Physics 2024-07-31 Yu-Mei Wu , Yan-Chen Bi , Qing-Guo Huang

We propose that the recent observations reported by the different Pulsar Timing Array (PTA) collaborations (i.e.~IPTA, EPTA, PPTA, and NANOGrav) of a common process over several pulsars could correspond to a stochastic gravitational wave…

General Relativity and Quantum Cosmology · Physics 2022-05-20 Alberto Roper Pol

The subtle influence of gravitational waves on the apparent positioning of celestial bodies offers novel observational windows. We calculate the expected astrometric signal induced by an isotropic Stochastic Gravitational Wave Background…

General Relativity and Quantum Cosmology · Physics 2025-10-27 Giorgio Mentasti , Carlo R. Contaldi

Pulsar Timing Array (PTA) collaborations recently reported evidence for the presence of a gravitational wave background (GWB) in their datasets. The main candidate that is expected to produce such a GWB is the population of supermassive…

In this study, we investigate the scenario in which the stochastic signal arises from primordial gravitational waves. Within this framework, we consider two distinct possibilities: one in which the pulsar timing arrays (PTAs) signal…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-24 Jun Li , Guanghai Guo , Pengfei Yan

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…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-25 N. M. Jiménez Cruz , Ameek Malhotra , Gianmassimo Tasinato , Ivonne Zavala

We investigate the effects of gravitational waves (GWs) from a simulated population of binary super-massive black holes (SMBHs) on pulsar timing array datasets. We construct a distribution describing the binary SMBH population from an…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 V. Ravi , J. S. B. Wyithe , G. Hobbs , R. M. Shannon , R. N. Manchester , D. R. B. Yardley , M. J. Keith

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

Direct detection of low-frequency gravitational waves ($10^{-9} - 10^{-8}$ Hz) is the main goal of pulsar timing array (PTA) projects. One of the main targets for the PTAs is to measure the stochastic background of gravitational waves (GWB)…

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

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

Recently, the Hellings Downs correlation has been observed by different pulsar timing array (PTA) collaborations, such as NANOGrav, European PTA, Parkes PTA, and Chinese PTA. These PTA measurements of the most precise pulsars within the…

High Energy Physics - Phenomenology · Physics 2024-12-02 Jing Yang , Ning Xie , Fa Peng Huang

Several Pulsar Timing Array (PTA) collaborations have recently found evidence for a Gravitational Wave Background (GWB) by measuring the perturbations that this background induces in the time-of-arrivals of pulsar signals. These…

Cosmology and Nongalactic Astrophysics · Physics 2025-06-03 Thomas Konstandin , Anna-Malin Lemke , Andrea Mitridate , Enrico Perboni

While pulsar timing array (PTA) collaborations have reported evidence for a stochastic gravitational wave background (GWB), the detection of continuous gravitational waves (GWs) from a confirmed supermassive black hole binary (SMBHB) would…

Astrophysics of Galaxies · Physics 2025-10-13 Li-Wen Tian , Yan-Chen Bi , Yu-Mei Wu , Qing-Guo Huang

Pulsar timing arrays (PTAs) will enable the detection of nanohertz gravitational waves (GWs) from a population of supermassive binary black holes (SMBBHs) in the next $\sim 3-7$ years. In addition, PTAs provide a rare opportunity to probe…

General Relativity and Quantum Cosmology · Physics 2019-07-12 Xavier Siemens , Jeffrey S. Hazboun , Paul T. Baker , Sarah Burke-Spolaor , Dustin Madison , Chiara Mingarelli , Joseph Simon , Tristan Smith

Pulsar Timing Arrays (PTA) around the world are using the incredible consistency of millisecond pulsars to measure low frequency gravitational waves from (super)Massive Black Hole (MBH) binaries. We use comprehensive MBH merger models based…

High Energy Astrophysical Phenomena · Physics 2017-09-06 Luke Zoltan Kelley , Laura Blecha , Lars Hernquist , Alberto Sesana , Stephen R. Taylor

A large population of binary systems in the Universe emitting gravitational waves (GW) would produce a stochastic noise, known as the gravitational wave background (GWB). The properties of the GWB directly depend on the attributes of its…

General Relativity and Quantum Cosmology · Physics 2024-12-04 Mikel Falxa , Hippolyte Quelquejay Leclere , Alberto Sesana

We consider the effects of relaxing the assumption that gravitational waves composing the stochastic gravitational wave background (SGWB) are uncorrelated between frequencies in analyses of the data from Pulsar Timing Arrays (PTAs). While…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-30 Wayne Hu , Qiuyue Liang , Meng-Xiang Lin , Mark Trodden

Fermi LAT observations of gamma-ray pulsars can be used to build a pulsar timing array (PTA) experiment to search for gravitational wave (GW) signals at nanohertz frequencies. At those frequencies, the dominant signal is expected to be a…

Gravitational waves (GWs) at ultra-low frequencies (${\lesssim 100\,\mathrm{nHz}}$) are key to understanding the assembly and evolution of astrophysical black hole (BH) binaries with masses $\sim 10^{6}-10^{9}\,M_\odot$ at low redshifts.…

Cosmology and Nongalactic Astrophysics · Physics 2021-10-26 Christopher J. Moore , Alberto Vecchio