Related papers: Axion Astrophysics
Within the next few years, GAIA and several instruments aiming at imag- ing extrasolar planets will see first light. In parallel, low mass planets are being searched around red dwarfs which offer more favourable conditions, both for radial…
Neutron stars are one of the most extreme objects in the universe, with densities that can exceed those of atomic nuclei and gravitational fields that are among the strongest known. Theoretical and observational research on neutron stars…
Modified theories of gravity have received a renewed interest due to their ability to account for the cosmic acceleration. In order to satisfy the solar system tests of gravity, these theories need to include a screening mechanism that…
White dwarfs and neutron stars are stellar objects with masses comparable to that of our sun. However, as the endpoint stages of stellar evolution, these objects do not sustain any thermonuclear burning and therefore can no longer support…
Compact objects such as neutron stars and white dwarfs can source axion-like particles and QCD axions due to CP-violating axion-fermion couplings. The magnitude of the axion field depends on the stellar density and on the strength of the…
Axion-like particles (ALPs), a class of pseudoscalars common to many extensions of the Standard Model, have the capacity to drain energy from the interiors of stars. Consequently, stellar evolution can be used to derive many constraints on…
A possibility to constrain axion-like particles from precision atomic physics is considered.
We review the current status of the anomalies in stellar cooling and argue that, among the new physics candidates, an axion-like particle would represent the best option to account for the hinted additional cooling.
Studying the physical processes occurring in the region just above the magnetic poles of strongly magnetized, accreting binary neutron stars is essential to our understanding of stellar and binary system evolution. Perhaps more importantly,…
Many stars -- if they could be imaged with enough angular resolution -- would exhibit features expected from theory but not possible to extract from spectra. We may group these by increasing complexity as follows. First, smooth variations…
X-ray observations of bright AGNs in or behind galaxy clusters offer unique capabilities to constrain axion-like particles (ALPs). Existing analysis technique rely on measurements of the global goodness-of-fit. We develop a new analysis…
The observed properties of stars and especially the neutrino signal of the supernova 1987A provide an upper limit to the axion mass, while the age and expansion rate of the universe provide a lower limit. There remains a "window of…
We perform a linear mode analysis of a uniformly distributed cloud of axion-like particles (ALPs) embedded in a magnetized intergalactic medium, in order to investigate the stability of axion stars under realistic astrophysical conditions.…
Nearly massless axion-like particles are of interest for astrophysical observations, and some constraints on their parameter space do exist in the literature. Here, we propose to put new constraints on these particles using polarisation…
In light-shining-through-walls experiments, axions and axion-like particles (ALPs) are searched for by exposing an optically thick barrier to a laser beam. In a magnetic field, photons could convert into ALPs in front of the barrier and…
When axion stars fly through an astrophysical magnetic background, the axion-to-photon conversion may generate a large electromagnetic radiation power. After including the interference effects of the spacially-extended axion-star source and…
Neutron stars are the densest, directly observable stellar objects in the universe and serve as unique astrophysical laboratories to study the behavior of matter under extreme physical conditions. This book chapter is devoted to describing…
Among the possible extensions of General Relativity that have been put forward in order to address some long standing issues in our understanding of the Universe, Scalar-Tensor Theories have received a lot of attention for their simplicity.…
In this work we revisit five different point sources within or behind galaxy clusters in order to constrain the coupling constant between axion-like particles (ALPs) and photons. We use three distinct machine learning (ML) techniques and…
The thermal evolution of a neutron star is studied by including the energy loss due to axion emission. Two axion models and three types of neutron-star matter equation of state are used with the effects of nucleon superfluidity properly…