Related papers: Multimessenger signals from compact axion star mer…
Binary neutron star mergers, such as the multimessenger GW170817 event, may produce hypermassive compact objects which are supported against collapse by the internal circulation of the fluid within the star. We compute their unstable modes…
The coalescence of a neutron-star binary is likely to result in the formation of a neutron-star merger remnant for a large range of binary mass configurations. The massive merger remnant shows strong oscillations, which are excited by the…
Axion-like particles (ALPs) can be copiously produced in binary neutron star (BNS) mergers through nucleon-nucleon bremsstrahlung if the ALP-nucleon couplings $g_{a N}$ are sizable. The ALP-photon coupling $g_{a\gamma}$ may trigger…
Rotating and oscillating neutron stars can give rise to long-lived Continuous Gravitational Waves (CGWs). Despite many years of searching, the detection of such a CGW signal remains elusive. In this article we describe the main…
Cosmological structure formation simulations of ultralight axion-like dark matter have shown that an axion star forms at the center of every dark matter halo in the Universe. These axion stars would then form in large numbers during the…
The first detection of a binary neutron star merger through gravitational waves and photons marked the dawn of multi-messenger astronomy with gravitational waves, and it greatly increased our insight in different fields of astrophysics and…
Gauged boson stars are exotic compact objects that can potentially mimic black holes or magnetized neutron stars in both their gravitational and electromagnetic signatures, offering a compelling new description or even an alternative…
The QCD axion is a hypothetical particle motivated by the Strong CP problem of particle physics. One of the primary ways in which its existence can be inferred is via its function as an additional cooling channel in stars, with some of the…
Gravitational wave astronomy might allow us to detect the coalescence of low-brightness astrophysical compact objects which are extremely difficult to be observed with current electromagnetic telescopes. Besides classical sources like black…
Axion stars, gravitationally bound states of low-energy axion particles, have a maximum mass allowed by gravitational stability. Weakly bound states obtaining this maximum mass have sufficiently large radii such that they are dilute, and as…
It is widely believed that axions are ubiquitous in string theory and could be the dark matter. The peculiar features of the axion dark matter are coherent oscillations and a coupling to the electromagnetic field through the Chern-Simons…
Binary neutron star mergers are rich laboratories for physics, accessible with ground-based interferometric gravitational-wave detectors such as the Advanced LIGO and Advanced Virgo. If a neutron star remnant survives the merger, it can…
The late stage of an inspiraling neutron star binary gives rise to strong gravitational wave emission due to its highly dynamic, strong gravity. Moreover, interactions between the stellar magnetospheres can produce considerable…
If dark matter is composed of axions, then axion stars form in the cores of dark matter halos. These stars are unstable above a critical mass, decaying to radio photons that heat the intergalactic medium, offering a new channel for axion…
Recent detections by the gravitational wave facilities LIGO/Virgo have opened a window to study the internal structure of neutron stars through the gravitational waves emitted during their coalescence. In this work we explore, through…
On 17 August 2017, less than two years after the direct detection of gravitational radiation from the merger of two ~30 Msun black holes, a binary neutron star merger was identified as the source of a gravitational wave signal of ~100 s…
The detection of gravitational waves emitted during a neutron star - black hole merger and the associated electromagnetic counterpart will provide a wealth of information about stellar evolution nuclear matter, and General Relativity. While…
The metastable hypermassive neutron star produced in the coalescence of two neutron stars can copiously produce axions that radiatively decay into $\mathcal{O}(100)$~MeV photons. These photons can form a fireball with characteristic…
Remnants of neutron-star mergers are essentially massive, hot, differentially rotating neutron stars, which are initially strongly oscillating. They represent a unique probe for high-density matter because the oscillations are detectable…
If the dark matter particles are axions, gravity can cause them to coalesce into axion stars, which are stable gravitationally bound systems of axions. In the previously known solutions for axion stars, gravity and the attractive force…