Related papers: Limits on the speed of gravitational waves from pu…
The propagation of gravitational waves is explored in the cosmological context. It is explicitly demonstrated that the propagation of gravitational waves could be influenced by the medium. It is shown that in the thermal radiation, the…
Efforts to detect gravitational waves by timing an array of pulsars have focused traditionally on stationary gravitational waves: e.g., stochastic or periodic signals. Gravitational wave bursts --- signals whose duration is much shorter…
In this paper we show in a covariant and gauge invariant way that in general relativity, tidal forces are actually a hidden form of gravitational waves. This must be so because gravitational effects cannot occur faster than the speed of…
The recent discovery of a $\gamma$-ray counterpart to a gravitational wave event has put extremely stringent constraints on the speed of gravitational waves at the present epoch. In turn, these constraints place strong theoretical pressure…
We revisit alternative mechanisms of gravitational wave production during inflation and argue that they generically emit a non-negligible amount of scalar fluctuations. We find the scalar power is larger than the tensor power by a factor of…
In light of the newly opened and rapidly growing gravitational waves window in multi-messenger astronomy, in order to fully take advantage of the new opportunities we are provided with, new ideas are required for a better and deeper employ…
Gravitational-wave astronomy provides a promising avenue for the discovery of new physics beyond general relativity as it probes extreme curvature and ultra-relativistic dynamics. However, in the absence of a compelling alternative to…
The sensitivity of pulsar timing arrays to gravitational waves is, at some level, limited by timing noise. Red timing noise - the stochastic wandering of pulse arrival times with a red spectrum - is prevalent in slow-spinning pulsars and…
It is shown that a gravitationally bound system with a one-dimensional velocity dispersion sigma can at most dissipate a fraction ~36(sigma/c)^3 of the gravitational wave energy propagating through it, even if their dynamical time is…
Pulsars are wonderful gravitational probes. Their tiny size and stellar mass give their rotation periods a stablility comparable to that of atomic frequency standards. This is especially true of the rapidly rotating "millisecond pulsars"…
We demonstrate that the late time oscillatory tails of massive gravitons, present in both massive theories of gravity and effectively in extra-dimensional scenarios, could potentially contribute to gravitational waves with very long…
In its final year of inspiral, a stellar mass ($1 - 10 M_\odot$) body orbits a massive ($10^5 - 10^7 M_\odot$) compact object about $10^5$ times, spiralling from several Schwarzschild radii to the last stable orbit. These orbits are deep in…
Ultralight boson fields, with a mass around $10^{-23}\text{eV}$, are promising candidates for the elusive cosmological dark matter. These fields induce a periodic oscillation of the spacetime metric in the nanohertz frequency band, which is…
Waves propagating through a gravitational potential exhibit wave-optics effects when their wavelength is not significantly smaller than the lensing scales. We study the propagation of a scalar wave, governed by the Klein-Gordon equation in…
Pulsar timing array projects are carrying out high precision observations of millisecond pulsars with the aim of detecting ultra-low frequency (~ 10^{-9} to 10^{-8} Hz) gravitational waves. We show how unambiguous detections of such waves…
We investigate the propagation of scalar waves induced by matter sources in the context of scalar-tensor theories of gravity which include screening mechanisms for the scalar degree of freedom. The usual approach when studying these…
If a set of massive objects collide in space and the fragments disperse, possibly forming black holes, then this process will emit gravitational waves. Computing the detailed gravitational wave-form associated with this process is a…
It is of fundamental importance to know the mass of gravitons. A simple method for constraining the graviton mass is to compare the arrival time of light and that of gravitational waves provided that both waves are simultaneously emitted…
Gravitational radiation that propagates through an inhomogeneous mass distribution is subject to random gravitational lensing, or scattering, causing variations in the wave amplitude and temporal smearing of the signal. A statistical theory…
In this paper, we explore the feasibility of detecting gravitomagnetic effects generated by gravitational waves, by monitoring the relative orientation of the angular momentum vectors of test particles. We analyze the response of the…