Related papers: When Tiny Halos Stir Spacetime: Gravitational Wave…
Primordial Black Holes (PBH) can form in the early universe and might comprise a significant fraction of the dark matter. Interestingly, they are accompanied by the generation of Gravitational Wave (GW) signals and they could contribute to…
Dark matter could be composed of compact dark objects (CDOs). A close binary of CDOs orbiting in the interior of solar system bodies can be a loud source of gravitational waves (GWs) for the LIGO and VIRGO detectors. We perform the first…
Axions are considered as a candidate of dark matter. The axions form coherent clouds which delay and amplify gravitational waves (GWs) at a resonant frequency. That is, the coherent axion clouds produce secondary GWs following a primary…
Gravitational wave interferometers have studied compact object mergers and solidified our understanding of strong gravity. Their increasing precision raises the possibility of detecting new physics, especially in a neutron star binary…
Matter and dark matter in galaxies represent two main components linked by the gravitational interaction. Collisions of galaxies may create an offset between the centers of mass of these components. Ignoring internal dynamics of particles…
Cold dark matter may form dense structures around supermassive black holes (SMBHs), significantly influencing their local environments. These dense regions are ideal sites for the formation of extreme mass-ratio inspirals (EMRIs), in which…
In previous work, we established theoretical results concerning the effect of matter shells surrounding a gravitational wave (GW) source, and we now apply these results to astrophysical scenarios. Firstly, it is shown that GW echoes that…
The transformation of powerful gravitational waves, created by the coalescence of massive black hole binaries, into electromagnetic radiation in external magnetic fields is revisited. In contrast to the previous calculations of the similar…
Just like light, gravitational waves (GWs) are deflected and magnified by gravitational fields as they propagate through the Universe. However, their low frequency, phase coherence and feeble coupling to matter allow for distinct lensing…
A dark matter overdensity around a black hole may significantly alter the dynamics of the black hole's merger with another compact object. We consider here intermediate mass-ratio inspirals of stellar-mass compact objects with…
In the pre-reheating era, following cosmic inflation and preceding radiation domination, the energy density may be dominated by an oscillating massive scalar condensate, such as is the case for quadratic chaotic inflation. We have found in…
Cold Dark Matter particles may interact with ordinary particles through a dark photon, which acquires a mass thanks to a spontaneous symmetry breaking mechanism. We discuss a dark photon model in which the scalar singlet associated to the…
This paper studies gravitational waves in a dark matter model composed of three types of particles with distinct spins, along with a scalar field $\phi$ that mediates interactions between Standard Model particles and dark matter. It…
The instability of dark matter may produce visible signals in the spectrum of cosmic gamma-rays. We consider this possibility in frameworks with additional spatial dimensions and supersymmetry. Examples of particles include…
The evolution of halos consisting of weakly self-interacting dark matter particles is summarized. The halos initially contain a central density cusp as predicted by cosmological models. Weak self-interaction leads to the formation of an…
Contemporary astronomy is undergoing a revolution, perhaps even more important than that which took place with the advent of radioastronomy in the 1960s, and then the opening of the sky to observations in the other electromagnetic…
Causal soliton formation (e.g. oscillons, Q-balls) in the primordial Universe is expected to give rise to a universal gravitational wave (GW) background, at frequencies smaller than scales of nonlinearity. We show that modifications of the…
We investigate the generation of gravitational waves due to the gravitational instability of primordial density perturbations in an early matter-dominated era which could be detectable by experiments such as LIGO and LISA. We use…
First order phase transitions in the early universe can give rise to a stochastic background of gravitational waves. A hypothetical first order electroweak phase transition is particularly interesting in this respect, since the signal is in…
We discuss a novel mechanism to generate gravitational waves in the early universe. A standard way to produce primordial black holes is to enhance at small-scales the overdensity perturbations generated during inflation. The latter, upon…