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

2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Jun’ichi Yokoyama

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.

2012 ◽  
Vol 8 (S291) ◽  
pp. 177-177
Author(s):  
Ryan Shannon

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.


2013 ◽  
Vol 22 (01) ◽  
pp. 1341008 ◽  
Author(s):  
BHAL CHANDRA JOSHI

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.


Symmetry ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 2418
Author(s):  
Michele Maiorano ◽  
Francesco De Paolis ◽  
Achille A. Nucita

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.


2005 ◽  
Vol 22 (3) ◽  
pp. 179-183 ◽  
Author(s):  
George Hobbs

AbstractThe number of known millisecond pulsars has dramatically increased in the last few years. Regular observations of these pulsars may allow gravitational waves with frequencies ∼10−9 Hz to be detected. A ‘pulsar timing array’ is therefore complimentary to other searches for gravitational waves using ground-based or space-based interferometers that are sensitive to much higher frequencies. In this review we describe (1) the basic methods for using an array of pulsars as a gravitational wave detector, (2) the sources of the potentially detectable waves, (3) current limits on individual sources and a stochastic background, and (4) the new project recently started using the Parkes radio telescope.


2009 ◽  
Vol 26 (2) ◽  
pp. 103-109 ◽  
Author(s):  
G. B. Hobbs ◽  
M. Bailes ◽  
N. D. R. Bhat ◽  
S. Burke-Spolaor ◽  
D. J. Champion ◽  
...  

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.


2012 ◽  
Vol 425 (2) ◽  
pp. 1597-1597 ◽  
Author(s):  
R. van Haasteren ◽  
Y. Levin ◽  
G. H. Janssen ◽  
K. Lazaridis ◽  
M. Kramer ◽  
...  

2011 ◽  
Vol 414 (2) ◽  
pp. 1777-1787 ◽  
Author(s):  
D. R. B. Yardley ◽  
W. A. Coles ◽  
G. B. Hobbs ◽  
J. P. W. Verbiest ◽  
R. N. Manchester ◽  
...  

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