COMMENTS ON COSMOLOGICAL GRAVITATIONAL WAVES BACKGROUND AND PULSAR TIMINGS

1989 ◽  
Vol 04 (09) ◽  
pp. 799-806 ◽  
Author(s):  
M. SIGNORE ◽  
N. SÁNCHEZ
Keyword(s):  
Elementary Particle ◽  
Gravitational Waves ◽  
Gravity Waves ◽  
Cosmic String ◽  
Upper Bounds ◽  
Millisecond Pulsar ◽  
Binary Pulsar ◽  
Long Wavelength ◽  
Upper Limits ◽  
Particle Phenomenology

We discuss the constraints on the stronger sources of the cosmological gravitational waves background detectable by millisecond pulsars—upper bounds on the cosmic string parameter Gµ, on the anisotropy Δ of the QCD transition phase and, on the dimensionless gravity wave energy. We derive also upper limits on the string parameter from the future binary pulsar timings and confront them with those imposed by current elementary particle phenomenology. We wait for future observations and for new experiments which either detect or place significant constraints on the existence of strings and long wavelength gravity waves—millisecond pulsar plus binary pulsar and the COBE cosmic 3 K anisotropy experiment.

scholarly journals Progress Report on the Binary Pulsar 1913+16

1979 ◽  
Vol 32 (2) ◽  
pp. 35 ◽  
Author(s):  
LA Fowler ◽  
JM Cordes ◽  
JH Taylor
Keyword(s):  
Gravitational Waves ◽  
Rotational Frequency ◽  
Relativity Theory ◽  
Current Status ◽  
Present Measurement ◽  
Orbital Inclination ◽  
Binary Pulsar ◽  
Upper Limits ◽  
Specific Prediction ◽  
The Individual

We report on the current status of observations of the binary pulsar PSRI913+16. The average pulse shape, polarization and spectrum have been found to be similar to those of other pulsars. We find no evidence for irregularities in the rotational frequency of the pulsar. With present measurement uncertainties, timing measurements after a few more years will yield estimates of the individual masses of the pulsar and its companion. the orbital inclination and the derivative of the orbital period. Upper limits on the last parameter are already inconsistent with theories that predict dipole gravitational waves; its measurement will test a specific prediction of general relativity theory and will indirectly demonstrate the existence of gravitational waves.

scholarly journals Searching for gravitational-wave bursts from cosmic string cusps with the Parkes Pulsar Timing Array

2020 ◽  
Vol 501 (1) ◽  
pp. 701-712
Author(s):  
N Yonemaru ◽  
S Kuroyanagi ◽  
G Hobbs ◽  
K Takahashi ◽  
X-J Zhu ◽  
...  
Keyword(s):  
False Alarm ◽  
Gravitational Wave ◽  
Cosmic String ◽  
Cosmic Strings ◽  
False Alarm Probability ◽  
String Tension ◽  
Detection Algorithm ◽  
Pulsar Timing ◽  
Upper Limits ◽  
Pulsar Timing Array

ABSTRACT Cosmic strings are potential gravitational-wave (GW) sources that can be probed by pulsar timing arrays (PTAs). In this work we develop a detection algorithm for a GW burst from a cusp on a cosmic string, and apply it to Parkes PTA data. We find four events with a false alarm probability less than 1 per cent. However further investigation shows that all of these are likely to be spurious. As there are no convincing detections we place upper limits on the GW amplitude for different event durations. From these bounds we place limits on the cosmic string tension of Gμ ∼ 10−5, and highlight that this bound is independent from those obtained using other techniques. We discuss the physical implications of our results and the prospect of probing cosmic strings in the era of Square Kilometre Array.

scholarly journals Constraints on ultra-low-frequency gravitational waves with statistics of pulsar spin-down rates

2019 ◽  
Vol 489 (3) ◽  
pp. 3547-3552
Author(s):  
Hiroki Kumamoto ◽  
Yuya Imasato ◽  
Naoyuki Yonemaru ◽  
Sachiko Kuroyanagi ◽  
Keitaro Takahashi
Keyword(s):  
Black Hole ◽  
Gravitational Waves ◽  
Time Derivative ◽  
Low Frequency ◽  
Upper Bounds ◽  
Galactic Centre ◽  
Frequency Range ◽  
Rate Distribution ◽  
Black Hole Binaries ◽  
Supermassive Black Hole

Abstract We probe ultra-low-frequency gravitational waves (GWs) with statistics of spin-down rates of millisecond pulsars (thereafter MSPs) by a method proposed in our previous work. The considered frequency range is 10−12 Hz ≲ fGW ≲ 10−10  Hz . The effect of such low-frequency GWs appears as a bias to spin-down rates that has a quadrupole pattern in the sky. We use the skewness of the spin-down rate distribution and the number of MSPs with negative spin-down rates to search for the bias induced by GWs. Applying this method to 149 MSPs selected from the ATNF pulsar catalogue, we derive upper bounds on the time derivative of the GW amplitudes of $\dot{h} \lt 6.2 \times 10^{-18}~{\rm s}^{-1}$ and $\dot{h} \lt 8.1 \times 10^{-18}~{\rm s}^{-1}$ in the directions of the Galactic Centre and M87, respectively. Approximating the GW amplitude as $\dot{h} \sim 2 \pi f_{\rm GW} h$, the bounds translate into h < 3 × 10−8 and h < 4 × 10−8, respectively, for fGW = 1/(1000 yr). Finally, we give the implications to possible supermassive black hole binaries at these sites.

scholarly journals Upper Limits on a Stochastic Background of Gravitational Waves

2005 ◽  
Vol 95 (22) ◽  
Author(s):  
B. Abbott ◽  
R. Abbott ◽  
R. Adhikari ◽  
J. Agresti ◽  
P. Ajith ◽  
...  
Keyword(s):  
Gravitational Waves ◽  
Stochastic Background ◽  
Upper Limits

scholarly journals First all-sky upper limits from LIGO on the strength of periodic gravitational waves using the Hough transform

2005 ◽  
Vol 72 (10) ◽  
Author(s):  
B. Abbott ◽  
R. Abbott ◽  
R. Adhikari ◽  
A. Ageev ◽  
J. Agresti ◽  
...  
Keyword(s):  
Gravitational Waves ◽  
Hough Transform ◽  
Upper Limits

scholarly journals DOES A DYNAMICAL SYSTEM LOSE ENERGY BY EMITTING GRAVITATIONAL WAVES?

1999 ◽  
Vol 14 (23) ◽  
pp. 1531-1537 ◽  
Author(s):  
F. I. COOPERSTOCK
Keyword(s):  
Dynamical System ◽  
Gravitational Waves ◽  
Gravity Waves ◽  
Energy Momentum Tensor ◽  
Momentum Tensor ◽  
Radiation Damping ◽  
Kinetic Term ◽  
Standard Rate ◽  
Gravitational Contribution ◽  
Actual Mass

We note that Eddington's radiation damping calculation of a spinning rod fails to account for the complete mass integral as given by Tolman. The missing stress contributions precisely cancel the standard rate given by the "quadrupole formula". This indicates that while the usual "kinetic" term can properly account for dynamical changes in the source, the actual mass is conserved. Hence gravity waves are not carriers of energy in vacuum. This supports the hypothesis that energy including the gravitational contribution is confined to regions of nonvanishing energy–momentum tensor Tik.

scholarly journals Near-field expansion of the metric due to a cosmic string

1999 ◽  
Vol 41 (2) ◽  
pp. 180-197
Author(s):  
Malcolm Anderson
Keyword(s):  
Gravitational Field ◽  
Gravitational Waves ◽  
Geometric Structure ◽  
Cosmic String ◽  
Travelling Waves ◽  
Near Field ◽  
World Sheet ◽  
The World

AbstractBy erecting a co-ordinate system tailored to the geometry of a cosmic string and examining the properties of the near gravitational field, it is possible to distinguish two types of gravitational waves supported by a general string metric. The first type, travelling waves, are completely decoupled from the curvature of the world sheet, whereas the second type, which I choose to call curvature waves, are generated in response to any non-trivial geometric structure on the string.

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