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

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Pulsar Timing Array (PTA) collaborations gather high-precision timing measurements of pulsars with the aim of detecting gravitational wave (GW) signals. A major challenge lies in the identification and characterization of the different…

Recent years have seen a burgeoning interest in using pulsar timing arrays (PTAs) as gravitational-wave (GW) detectors. To date, that interest has focused mainly on three particularly promising source types: supermassive--black-hole…

General Relativity and Quantum Cosmology · Physics 2014-02-26 Curt Cutler , Sarah Burke-Spolaor , Michele Vallisneri , Joseph Lazio , Walid Majid

Pulsar timing arrays have found evidence for a low-frequency gravitational wave background (GWB). Assuming the GWB is produced by supermassive black hole binaries (SMBHBs), the next gravitational wave (GW) signals astronomers anticipate are…

High Energy Astrophysical Phenomena · Physics 2024-04-24 Emiko C. Gardiner , Luke Zoltan Kelley , Anna-Malin Lemke , Andrea Mitridate

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

Pulsar Timing Arrays (PTAs) have reported evidence for a stochastic gravitational wave (GW) background at nHz frequencies, possibly originating in the early Universe. We show that the spectral shape of the low-frequency (causality) tail of…

Cosmology and Nongalactic Astrophysics · Physics 2024-07-25 Gabriele Franciolini , Davide Racco , Fabrizio Rompineve

The observations from pulsar timing arrays (PTAs), led by the North American Nanohertz Observatory for Gravitational Waves (NANOGrav), have provided opportunities to constrain primordial gravitational waves at low frequencies. In this…

Cosmology and Nongalactic Astrophysics · Physics 2025-05-07 Lu Yin

Transient gravitational waves (aka gravitational wave bursts) within the nanohertz frequency band could be generated by a variety of astrophysical phenomena such as the encounter of supermassive black holes, the kinks or cusps in cosmic…

General Relativity and Quantum Cosmology · Physics 2023-07-13 Heling Deng , Bence Bécsy , Xavier Siemens , Neil J. Cornish , Dustin R. Madison

The pulsar timing array (PTA) collaborations have recently suggested the presence of a gravitational wave background at nano-Hertz frequencies. In this paper, we explore potential inflationary interpretation of this signal within the…

Cosmology and Nongalactic Astrophysics · Physics 2023-11-14 Chengjie Fu , Jing Liu , Xing-Yu Yang , Wang-Wei Yu , Yawen Zhang

A new detection method for ultra-low frequency gravitational waves (GWs) with a frequency much lower than the observational range of pulsar timing arrays (PTAs) was suggested in Yonemaru et al. (2016). In the PTA analysis, ultra-low…

High Energy Astrophysical Phenomena · Physics 2018-05-02 Naoyuki Yonemaru , Hiroki Kumamoto , Keitaro Takahashi , Sachiko Kuroyanagi

We search for an isotropic stochastic gravitational-wave background (GWB) in the $12.5$-year pulsar timing data set collected by the North American Nanohertz Observatory for Gravitational Waves. Our analysis finds strong evidence of a…

With pulsar timing arrays (PTAs) having observed a gravitational wave background (GWB) at nanohertz frequencies, the focus of the field is shifting towards determining and characterizing its origin. While the primary candidate is a…

Instrumentation and Methods for Astrophysics · Physics 2025-09-10 Kyle A. Gersbach , Stephen R. Taylor , Bence Bécsy , Anna-Malin Lemke , Andrea Mitridate , Nihan Pol

Abbreviated: We investigate the potential of detecting the gravitational wave from individual binary black hole systems using pulsar timing arrays (PTAs) and calculate the accuracy for determining the GW properties. This is done in a…

High Energy Astrophysical Phenomena · Physics 2015-05-27 K. J. Lee , N. Wex , M. Kramer , B. W. Stappers , C. G. Bassa , G. H. Janssen , R. Karuppusamy , R. Smits

Gravitational Waves (GWs) are tiny ripples in the fabric of space-time predicted by Einstein's General Relativity. Pulsar timing arrays (PTAs) are well poised to detect low frequency ($10^{-9}$ -- $10^{-7}$ Hz) GWs in the near future. There…

Instrumentation and Methods for Astrophysics · Physics 2015-06-04 J. A. Ellis , F. A. Jenet , M. A. McLaughlin

The stochastic gravitational wave background (SGWB) recently detected by the PTA collaborations could be the gravitational waves (GWs) induced by curvature perturbations. However, primordial black holes (PBHs) might be overproduced if the…

Cosmology and Nongalactic Astrophysics · Physics 2024-02-13 Keisuke Inomata , Masahiro Kawasaki , Kyohei Mukaida , Tsutomu T. Yanagida

The recent detection of a stochastic signal in the NANOGrav 15-year data set has aroused great interest in uncovering its origin. However, the evidence for the Hellings-Downs correlations, a key signature of the gravitational-wave…

Cosmology and Nongalactic Astrophysics · Physics 2024-05-07 Zu-Cheng Chen , Yu-Mei Wu , Yan-Chen Bi , Qing-Guo Huang

We discuss the interpretation of the detected signal by Pulsar Timing Array (PTA) observations as a gravitational wave background (GWB) of cosmological origin. We combine NANOGrav 15-years and EPTA-DR2new data sets and confront them against…

Cosmology and Nongalactic Astrophysics · Physics 2024-04-29 Daniel G. Figueroa , Mauro Pieroni , Angelo Ricciardone , Peera Simakachorn

The recently released data by pulsar timing array (PTA) collaborations have amassed substantial evidence corroborating the existence of a stochastic signal consistent with a gravitational-wave background at frequencies around the nanohertz…

Cosmology and Nongalactic Astrophysics · Physics 2025-03-27 Lang Liu , Zu-Cheng Chen , Qing-Guo Huang

We study a new source of stochastic gravitational wave background (SGWB) from the final collapse of a network of topological defects. Typically, the final collapse is considered negligible for generating gravitational waves (GWs) due to its…

General Relativity and Quantum Cosmology · Physics 2024-06-28 Shuailiang Ge

The stochastic gravitational-wave background is imprinted on the times of arrival of radio pulses from millisecond pulsars. Traditional pulsar timing analyses fit a timing model to each pulsar and search the residuals of the fit for a…

High Energy Astrophysical Phenomena · Physics 2023-11-13 William DeRocco , Jeff A. Dror