scholarly journals Pulsar timing array projects

2009 ◽  
Vol 5 (S261) ◽  
pp. 228-233
Author(s):  
G. Hobbs
Keyword(s):  
Solar System ◽  
Gravitational Waves ◽  
Time Scales ◽  
Direct Detection ◽  
Atomic Clocks ◽  
Millisecond Pulsars ◽  
Pulsar Timing ◽  
The Stability ◽  
Pulsar Timing Array ◽  
The Universe

AbstractPulsars are amongst the most stable rotators known in the Universe. Over many years some millisecond pulsars rival the stability of atomic clocks. Comparing observations of many such stable pulsars may allow the first direct detection of gravitational waves, improve the Solar System planetary ephemeris and provide a means to study irregularities in terrestrial time scales. Here we review the goals and status of current and future pulsar timing array projects.

scholarly journals Constraining the nanohertz gravitational wave background with the Parkes Pulsar Timing Array

2012 ◽  
Vol 8 (S291) ◽  
pp. 177-177
Author(s):  
Ryan Shannon
Keyword(s):  
Gravitational Wave ◽  
Gravitational Waves ◽  
Direct Detection ◽  
Massive Black Hole ◽  
Black Hole Binaries ◽  
Pulsar Timing ◽  
The Galaxy ◽  
Gravitational Wave Background ◽  
Pulsar Timing Array ◽  
The Universe

AbstractThe direct detection of gravitational waves will usher in a new era of astrophysics, enabling the study of regions of the universe opaque to electromagnetic radiation or electromagnetically quiet. An ensemble of pulsars (referred to as a pulsar timing array) provides a set of clocks distributed across the Galaxy sensitive to gravitational waves with periods on the order of five years (frequencies of many nanohertz). Plausible source of gravitational waves in this frequency band include massive black hole binaries in the throes of mergers and oscillating cosmic strings. The stochastic gravitational wave background, the sum of gravitational waves emitted throughout the universe, is the most likely signal to be detected by a pulsar timing array.While the detection of gravitational waves will be a milestone in pulsar astronomy, a constraining limit on the strength of the gravitational wave background can be used to constrain cosmological models and early Universe physics. Here we present a new algorithm that can be used to constrain the strength of the GWB with a pulsar timing array. We then apply this technique to Parkes Pulsar Timing Array observations and place a new limit on the strength of the GWB. We conclude by discussing the astrophysical implications of this limit and the prospects for detecting gravitational waves with pulsars.

scholarly journals The Parkes Pulsar Timing Array Project

2009 ◽  
Vol 5 (H15) ◽  
pp. 233-233
Author(s):  
R. N. Manchester
Keyword(s):  
Solar System ◽  
Gravitational Waves ◽  
Time Scale ◽  
Millisecond Pulsars ◽  
Pulsar Timing ◽  
Pulsar Timing Array

AbstractThe Parkes Pulsar Timing Array project is timing 20 millisecond pulsars with the aims of detecting gravitational waves, establishing a time scale based on pulsar periods and improving solar-system ephemerides.

scholarly journals Testing General Relativity with Pulsar Timing Arrays

2012 ◽  
Author(s):  
Sydney Chamberlin ◽  
Xavier Siemens
Keyword(s):  
General Relativity ◽  
Gravitational Waves ◽  
Direct Detection ◽  
Promising Tool ◽  
Pulsar Timing ◽  
Theories Of Gravity ◽  
Statistical Detection ◽  
Detection Strategies ◽  
Pulsar Timing Array ◽  
The Universe

Pulsar timing arrays are a promising tool for probing the universe through gravitational radiation. A variety of astrophysical and cosmological sources are expected to contribute to a stochastic background of gravitational waves (GWs) in the pulsar timing array (PTA) frequency band. Direct detection of GWs will provide a new mechanism to test General Relativity and requires the development of robust statistical detection strategies. Here, we investigate the overlap reduction function, a term present in the optimal detection statistic, for GWs in various metric theories of gravity. We show that PTA sensitivity increases for non-transverse gravitational waves when pulsar pairs have small angular separations in the sky. 

scholarly journals A pulsar-based time-scale from the International Pulsar Timing Array

2019 ◽  
Vol 491 (4) ◽  
pp. 5951-5965 ◽  
Author(s):  
G Hobbs ◽  
L Guo ◽  
R N Caballero ◽  
W Coles ◽  
K J Lee ◽  
...  
Keyword(s):  
Time Scales ◽  
Time Scale ◽  
Limiting Factor ◽  
Radio Pulsars ◽  
Pulsar Timing ◽  
The Us ◽  
The Stability ◽  
Solar System Dynamics ◽  
Noise Models ◽  
Pulsar Timing Array

ABSTRACT We have constructed a new time-scale, TT(IPTA16), based on observations of radio pulsars presented in the first data release from the International Pulsar Timing Array (IPTA). We used two analysis techniques with independent estimates of the noise models for the pulsar observations and different algorithms for obtaining the pulsar time-scale. The two analyses agree within the estimated uncertainties and both agree with TT(BIPM17), a post-corrected time-scale produced by the Bureau International des Poids et Mesures (BIPM). We show that both methods could detect significant errors in TT(BIPM17) if they were present. We estimate the stability of the atomic clocks from which TT(BIPM17) is derived using observations of four rubidium fountain clocks at the US Naval Observatory. Comparing the power spectrum of TT(IPTA16) with that of these fountain clocks suggests that pulsar-based time-scales are unlikely to contribute to the stability of the best time-scales over the next decade, but they will remain a valuable independent check on atomic time-scales. We also find that the stability of the pulsar-based time-scale is likely to be limited by our knowledge of solar-system dynamics, and that errors in TT(BIPM17) will not be a limiting factor for the primary goal of the IPTA, which is to search for the signatures of nano-Hertz gravitational waves.

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

2009 ◽  
Vol 26 (2) ◽  
pp. 103-109 ◽  
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.

scholarly journals Implication of pulsar timing array experiments on cosmological gravitational wave detection

2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Jun’ichi Yokoyama
Keyword(s):  
Gravitational Wave ◽  
Gravitational Waves ◽  
Electromagnetic Waves ◽  
Precision Measurements ◽  
Observational Result ◽  
Wave Detection ◽  
Pulsar Timing ◽  
Gravitational Wave Background ◽  
Pulsar Timing Array ◽  
The Universe

AbstractGravitational waves provide a new probe of the Universe which can reveal a number of cosmological and astrophysical phenomena that cannot be observed by electromagnetic waves. Different frequencies of gravitational waves are detected by different means. Among them, precision measurements of pulsar timing provides a natural detector for gravitational waves with light-year scale wavelengths. In this review, first a basic framework to detect a stochastic gravitational wave background using pulsar timing array is introduced, and then possible interpretations of the latest observational result of 12.5-year NANOGrav data are described.

scholarly journals Solar System Ephemerides, Pulsar Timing, Gravitational Waves, & Navigation

2017 ◽  
Vol 13 (S337) ◽  
pp. 150-153 ◽  
Author(s):  
T. Joseph W. Lazio ◽  
S. Bhaskaran ◽  
C. Cutler ◽  
W. M. Folkner ◽  
R. S. Park ◽  
...  
Keyword(s):  
Solar System ◽  
Gravitational Waves ◽  
Time Of Arrival ◽  
Millisecond Pulsars ◽  
The Past ◽  
The North ◽  
Spacecraft Navigation ◽  
Pulsar Timing ◽  
Multiple Spacecraft ◽  
The Times

AbstractIn-spiraling supermassive black holes should emit gravitational waves, which would produce characteristic distortions in the time of arrival residuals from millisecond pulsars. Multiple national and regional consortia have constructed pulsar timing arrays by precise timing of different sets of millisecond pulsars. An essential aspect of precision timing is the transfer of the times of arrival to a (quasi-)inertial frame, conventionally the solar system barycenter. The barycenter is determined from the knowledge of the planetary masses and orbits, which has been refined over the past 50 years by multiple spacecraft. Within the North American Nanohertz Observatory for Gravitational Waves (NANOGrav), uncertainties on the solar system barycenter are emerging as an important element of the NANOGrav noise budget. We describe what is known about the solar system barycenter, touch upon how uncertainties in it affect gravitational wave studies with pulsar timing arrays, and consider future trends in spacecraft navigation.

Beyond the Schwarzschild Metric

2018 ◽  
Author(s):  
David M. Wittman
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Gravitational Waves ◽  
Test Particle ◽  
Direct Detection ◽  
Relativistic Effects ◽  
Big Bang ◽  
Clusters Of Galaxies ◽  
General Relativistic ◽  
The Universe

General relativity explains much more than the spacetime around static spherical masses.We briefly assess general relativity in the larger context of physical theories, then explore various general relativistic effects that have no Newtonian analog. First, source massmotion gives rise to gravitomagnetic effects on test particles.These effects also depend on the velocity of the test particle, which has substantial implications for orbits around black holes to be further explored in Chapter 20. Second, any changes in the sourcemass ripple outward as gravitational waves, and we tell the century‐long story from the prediction of gravitational waves to their first direct detection in 2015. Third, the deflection of light by galaxies and clusters of galaxies allows us to map the amount and distribution of mass in the universe in astonishing detail. Finally, general relativity enables modeling the universe as a whole, and we explore the resulting Big Bang cosmology.

A Tale of Two Infinities

2021 ◽  
Author(s):  
Gianfranco Bertone
Keyword(s):  
Black Holes ◽  
Dark Matter ◽  
Gravitational Waves ◽  
Direct Detection ◽  
Traditional Approach ◽  
Fundamental Physics ◽  
Modern Cosmology ◽  
Nobel Prize In Physics ◽  
The Universe ◽  
Modern Astronomy

The spectacular advances of modern astronomy have opened our horizon on an unexpected cosmos: a dark, mysterious Universe, populated by enigmatic entities we know very little about, like black holes, or nothing at all, like dark matter and dark energy. In this book, I discuss how the rise of a new discipline dubbed multimessenger astronomy is bringing about a revolution in our understanding of the cosmos, by combining the traditional approach based on the observation of light from celestial objects, with a new one based on other ‘messengers’—such as gravitational waves, neutrinos, and cosmic rays—that carry information from otherwise inaccessible corners of the Universe. Much has been written about the extraordinary potential of this new discipline, since the 2017 Nobel Prize in physics was awarded for the direct detection of gravitational waves. But here I will take a different angle and explore how gravitational waves and other messengers might help us break the stalemate that has been plaguing fundamental physics for four decades, and to consolidate the foundations of modern cosmology.

Limiting and Detecting Gravitational Waves with a Pulsar Timing Array

2011 ◽  
Author(s):  
D. R. B. Yardley ◽  
W. A. Coles ◽  
G. B. Hobbs ◽  
R. N. Manchester ◽  
Marta Burgay ◽  
...  
Keyword(s):  
Gravitational Waves ◽  
Pulsar Timing ◽  
Pulsar Timing Array
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