The International Pulsar Timing Array: second data release

ABSTRACT In this paper, we describe the International Pulsar Timing Array second data release, which includes recent pulsar timing data obtained by three regional consortia: the European Pulsar Timing Array, the North American Nanohertz Observatory for Gravitational Waves, and the Parkes Pulsar Timing Array. We analyse and where possible combine high-precision timing data for 65 millisecond pulsars which are regularly observed by these groups. A basic noise analysis, including the processes which are both correlated and uncorrelated in time, provides noise models and timing ephemerides for the pulsars. We find that the timing precisions of pulsars are generally improved compared to the previous data release, mainly due to the addition of new data in the combination. The main purpose of this work is to create the most up-to-date IPTA data release. These data are publicly available for searches for low-frequency gravitational waves and other pulsar science.

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Identifying and mitigating noise sources in precision pulsar timing data sets

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa3411 ◽

2020 ◽

Author(s):

Boris Goncharov ◽

D J Reardon ◽

R M Shannon ◽

Xing-Jiang Zhu ◽

Eric Thrane ◽

...

Keyword(s):

Gravitational Waves ◽

Physical Models ◽

Dispersion Measure ◽

Data Sets ◽

Pulse Profile ◽

Noise Sources ◽

Arrival Times ◽

Pulsar Timing ◽

Noise Models ◽

Pulsar Timing Array

Abstract Pulsar timing array projects measure the pulse arrival times of millisecond pulsars for the primary purpose of detecting nanohertz-frequency gravitational waves. The measurements include contributions from a number of astrophysical and instrumental processes, which can either be deterministic or stochastic. It is necessary to develop robust statistical and physical models for these noise processes because incorrect models diminish sensitivity and may cause a spurious gravitational wave detection. Here we characterise noise processes for the 26 pulsars in the second data release of the Parkes Pulsar Timing Array using Bayesian inference. In addition to well-studied noise sources found previously in pulsar timing array data sets such as achromatic timing noise and dispersion measure variations, we identify new noise sources including time-correlated chromatic noise that we attribute to variations in pulse scattering. We also identify “exponential dip” events in four pulsars, which we attribute to magnetospheric effects as evidenced by pulse profile shape changes observed for three of the pulsars. This includes an event in PSR J1713+0747, which had previously been attributed to interstellar propagation. We present noise models to be used in searches for gravitational waves. We outline a robust methodology to evaluate the performance of noise models and identify unknown signals in the data. The detection of variations in pulse profiles highlights the need to develop efficient profile domain timing methods.

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PULSAR TIMING ARRAYS

International Journal of Modern Physics D ◽

10.1142/s0218271813410083 ◽

2013 ◽

Vol 22 (01) ◽

pp. 1341008 ◽

Cited By ~ 4

Author(s):

BHAL CHANDRA JOSHI

Keyword(s):

Gravitational Wave ◽

Gravitational Waves ◽

Low Frequency ◽

Radio Pulsars ◽

Very Low Frequency ◽

Pulsar Timing ◽

Gravitational Wave Background ◽

Pulsar Timing Array ◽

Current Operating

In the last decade, the use of an ensemble of radio pulsars to constrain the characteristic strain caused by a stochastic gravitational wave background has advanced the cause of detection of very low frequency gravitational waves (GWs) significantly. This electromagnetic means of GW detection, called Pulsar Timing Array (PTA), is reviewed in this paper. The principle of operation of PTA, the current operating PTAs and their status are presented along with a discussion of the main challenges in the detection of GWs using PTA.

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Gravitational wave research using pulsar timing arrays

National Science Review ◽

10.1093/nsr/nwx126 ◽

2017 ◽

Vol 4 (5) ◽

pp. 707-717 ◽

Cited By ~ 14

Author(s):

George Hobbs ◽

Shi Dai

Keyword(s):

Gravitational Wave ◽

High Precision ◽

Low Frequency ◽

Millisecond Pulsars ◽

Pulsar Timing ◽

Distributed Array ◽

The Status ◽

Wave Research ◽

Near Future ◽

Pulsar Timing Array

Abstract A pulsar timing array (PTA) refers to a program of regular, high-precision timing observations of a widely distributed array of millisecond pulsars. Here we review the status of the three primary PTA projects and the joint International Pulsar Timing Array project. We discuss current results related to ultra-low-frequency gravitational wave searches and highlight opportunities for the near future.

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Principles of Gravitational-Wave Detection with Pulsar Timing Arrays

Symmetry ◽

10.3390/sym13122418 ◽

2021 ◽

Vol 13 (12) ◽

pp. 2418

Author(s):

Michele Maiorano ◽

Francesco De Paolis ◽

Achille A. Nucita

Keyword(s):

Gravitational Wave ◽

Gravitational Waves ◽

Low Frequency ◽

Black Hole Binaries ◽

Pulsar Timing ◽

Time Correlations ◽

Array Detection ◽

Square Kilometer Array ◽

Gravitational Wave Background ◽

Pulsar Timing Array

Pulsar timing uses the highly stable pulsar spin period to investigate many astrophysical topics. In particular, pulsar timing arrays make use of a set of extremely well-timed pulsars and their time correlations as a challenging detector of gravitational waves. It turns out that pulsar timing arrays are particularly sensitive to ultra-low-frequency gravitational waves, which makes them complementary to other gravitational-wave detectors. Here, we summarize the basics, focusing especially on supermassive black-hole binaries and cosmic strings, which have the potential to form a stochastic gravitational-wave background in the pulsar timing array detection band, and the scientific goals on this challenging topic. We also briefly outline the recent interesting results of the main pulsar timing array collaborations, which have found strong evidence of a common-spectrum process compatible with a stochastic gravitational-wave background and mention some new perspectives that are particularly interesting in view of the forthcoming radio observatories such as the Five hundred-meter Aperture Spherical Telescope, the MeerKAT telescope, and the Square Kilometer Array.

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Pulsars Probe the Low-Frequency Gravitational Sky: Pulsar Timing Arrays Basics and Recent Results

Publications of the Astronomical Society of Australia ◽

10.1017/pasa.2018.7 ◽

2018 ◽

Vol 35 ◽

Cited By ~ 13

Author(s):

Caterina Tiburzi

Keyword(s):

Gravitational Waves ◽

Galaxy Formation ◽

Low Frequency ◽

Radio Telescopes ◽

Detection Algorithms ◽

Pulsar Timing ◽

Upper Limits ◽

New Generation ◽

Timing Models ◽

Pulsar Timing Array

AbstractPulsar Timing Array experiments exploit the clock-like behaviour of an array of millisecond pulsars, with the goal of detecting low-frequency gravitational waves. Pulsar Timing Array experiments have been in operation over the last decade, led by groups in Europe, Australia, and North America. These experiments use the most sensitive radio telescopes in the world, extremely precise pulsar timing models and sophisticated detection algorithms to increase the sensitivity of Pulsar Timing Arrays. No detection of gravitational waves has been made to date with this technique, but Pulsar Timing Array upper limits already contributed to rule out some models of galaxy formation. Moreover, a new generation of radio telescopes, such as the Five hundred metre Aperture Spherical Telescope and, in particular, the Square Kilometre Array, will offer a significant improvement to the Pulsar Timing Array sensitivity. In this article, we review the basic concepts of Pulsar Timing Array experiments, and discuss the latest results from the established Pulsar Timing Array collaborations.

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Gravitational-Wave Detection Using Pulsars: Status of the Parkes Pulsar Timing Array Project

Publications of the Astronomical Society of Australia ◽

10.1071/as08023 ◽

2009 ◽

Vol 26 (2) ◽

pp. 103-109 ◽

Cited By ~ 49

Author(s):

G. B. Hobbs ◽

M. Bailes ◽

N. D. R. Bhat ◽

S. Burke-Spolaor ◽

D. J. Champion ◽

...

Keyword(s):

Gravitational Wave ◽

Gravitational Waves ◽

Direct Detection ◽

Low Frequency ◽

Current Status ◽

Binary Black Holes ◽

Gravitational Wave Detection ◽

Wave Detection ◽

Pulsar Timing ◽

Pulsar Timing Array

AbstractThe first direct detection of gravitational waves may be made through observations of pulsars. The principal aim of pulsar timing-array projects being carried out worldwide is to detect ultra-low frequency gravitational waves (f ∼ 10−9–10−8 Hz). Such waves are expected to be caused by coalescing supermassive binary black holes in the cores of merged galaxies. It is also possible that a detectable signal could have been produced in the inflationary era or by cosmic strings. In this paper, we review the current status of the Parkes Pulsar Timing Array project (the only such project in the Southern hemisphere) and compare the pulsar timing technique with other forms of gravitational-wave detection such as ground- and space-based interferometer systems.

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Stochastic and continuous gravitational wave analysis pipelines for pulsar timing array data

Proceedings of the International Astronomical Union ◽

10.1017/s1743921312023551 ◽

2012 ◽

Vol 8 (S291) ◽

pp. 178-178

Author(s):

Justin Ellis ◽

Fredrick Jenet ◽

Xavier Siemens ◽

Maura McLaughlin

Keyword(s):

Data Analysis ◽

Gravitational Waves ◽

Recent Progress ◽

Simulated Data ◽

Wave Analysis ◽

Stochastic Background ◽

Pulsar Timing ◽

Timing Data ◽

Timing Models ◽

Pulsar Timing Array

AbstractThe Nanohertz Observatory for Gravitational Waves (NANOGrav) collaboration aims to detect gravitational waves (GWs) through the precise timing of millisecond pulsars. GWs will come in the form of a stochastic background, continuous sources and burst sources. Here we will review recent progress on the development of data analysis pipelines aimed at the detection of a stochastic background as well as continuous sources. We will introduce the Optimal Statistic and F-Statistic methods that are used in the stochastic and continuous pipelines, respectively. Both pipelines are fully functional on real pulsar timing data and take into account the timing models for each pulsar. Finally, we will present the efficacy of each pipeline on locally simulated data as well as data from the 2012 IPTA data challenge.

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Timing of binary pulsars and the search for the low-frequency gravitational waves

Proceedings of the International Astronomical Union ◽

10.1017/s1743921310008999 ◽

2009 ◽

Vol 5 (H15) ◽

pp. 234-234

Author(s):

Vladimir A. Potapov ◽

Sergei M. Kopeikin

Keyword(s):

Gravitational Waves ◽

Standard Procedure ◽

Low Frequency ◽

Correlated Noise ◽

Binary Pulsars ◽

Stochastic Fluctuations ◽

Pulsar Timing ◽

Timing Data ◽

Long Time ◽

The Times

AbstractMillisecond and binary pulsars are the most stable natural standards of astronomical time giving us a unique opportunity to search for gravitational waves (GW) and to test General Relativity. GWs from violent events in early Universe and from the ensemble of galactic and extragalactic objects perturb propagation of radio pulses from a pulsar to observer bringing about stochastic fluctuations in the times of arrival of the pulses (TOA). If one observes the pulsar over a sufficiently long time span, the fluctuations will be registered as a low-frequency, correlated noise affecting the timing residuals in the frequency range 10−12 ÷ 10−7 Hz. This work demonstrates how the standard procedure of processing of the pulsar timing data can bias the estimate of the upper limit on the density of the GW background (GWB).

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