Dilute and dense axion stars

  title={Dilute and dense axion stars},
  author={L. Visinelli and S. Baum and J. Redondo and K. Freese and F. Wilczek},
  journal={Physics Letters B},
Abstract Axion stars are hypothetical objects formed of axions, obtained as localized and coherently oscillating solutions to their classical equation of motion. Depending on the value of the field amplitude at the core | θ 0 | ≡ | θ ( r = 0 ) | , the equilibrium of the system arises from the balance of the kinetic pressure and either self-gravity or axion self-interactions. Starting from a general relativistic framework, we obtain the set of equations describing the configuration of the axion… Expand

Figures and Tables from this paper

Paper Mentions

Global view of QCD axion stars
Taking a comprehensive view, including a full range of boundary conditions, we reexamine QCD axion star solutions based on the relativistic Klein-Gordon equation (using the Ruffini-BonazzolaExpand
Formation of Relativistic Axion Stars
Axions and axion-like particles are compelling candidates for the missing dark matter of the universe. As they undergo gravitational collapse, they can form compact objects such as axion stars orExpand
Axion configurations around pulsars
Axion-like particles lead to a plethora of new phenomena relating to compact astrophysical objects including stellar and black hole superradiance, axion stars and axion clusters. In this work, weExpand
Diluted Axion Star Collisions with Neutron Stars
Diluted axion star, a self-gravitating object with the quantum pressure balancing gravity, has been predicted in many models with a QCD axion or axion-like particle. It can be formed in the earlyExpand
Parametric-resonance based phenomenology of gravitating axion configurations
One of the most compelling candidates for Dark Matter (DM) are light pseudo-scalar particles (axions), motivated by the strong CP problem and axiverse scenario in string theory. Depending on theirExpand
Parametric-resonance based phenomenology of gravitating axion configurations
One of the most compelling candidates for Dark Matter (DM) are light pseudo-scalar particles (axions), motivated by the strong CP problem and axiverse scenario in string theory. Depending on theirExpand
Early seeds of axion miniclusters
We study the small scale structure of axion dark matter in the post-inflationary scenario, which predicts the formation of low-mass, high density clumps of gravitationally bound axions called axionExpand
Large-misalignment mechanism for the formation of compact axion structures: Signatures from the QCD axion to fuzzy dark matter
Axions are some of the best motivated particles beyond the Standard Model. We show how the attractive self-interactions of dark matter (DM) axions over a broad range of masses, from $10^{-22}$ eV toExpand
Kerr black holes with synchronized axionic hair
We construct and analyse Kerr black holes (BHs) with synchronised axionic hair. These are the BH generalisations of the recently constructed rotating axion boson stars arXiv:2005.05982. Such BHs areExpand
Dipole radiation and beyond from axion stars in electromagnetic fields
We investigate the production of photons from coherently oscillating, spatially localized clumps of axionic fields (oscillons and axion stars) in the presence of external electromagnetic fields. WeExpand


Dense Axion Stars.
A new branch of dense axion stars is found in which gravity is balanced by the mean-field pressure of the axion Bose-Einstein condensate, and this branch could produce a bosenova, leaving a dense axions star as the remnant. Expand
Collapse of axion stars
A bstractAxion stars, gravitationally bound states of low-energy axion particles, have a maximum mass allowed by gravitational stability. Weakly bound states obtaining this maximum mass haveExpand
Nonlinear axion dynamics and the formation of cosmological pseudosolitons.
  • Kolb, Tkachev
  • Physics, Medicine
  • Physical review. D, Particles and fields
  • 1994
It is found that axion perturbations on scales corresponding to causally disconnected regions at [ital T][similar to]1 GeV can lead to very dense pseudosoliton configurations the authors call axitons, which evolve to axion miniclusters with a present density high enough to lead to Bose-Einstein relaxation in the gravitationally bound clumps of axions, forming Bose stars. Expand
Rotating drops of axion dark matter
We consider how QCD axions produced by the misalignment mechanism could form galactic dark matter halos. We recall that stationary, gravitationally stable axion field configurations have the size ofExpand
Dark matter axions revisited
We study for what specific values of the theoretical parameters the axion can form the totality of cold dark matter. We examine the allowed axion parameter region in the light of recent dataExpand
Searching for axions and ALPs from string theory
We review searches for closed string axions and axion–like particles (ALPs) in IIB string flux compactifications. For natural values of the background fluxes and TeV scale gravitino mass, the moduliExpand
Axion dark matter, solitons and the cusp–core problem
Self-gravitating bosonic fields can support stable and localised field configurations. For real fields, these solutions oscillate in time and are known as oscillatons. The density profile is static,Expand
Calculation of the axion mass based on high-temperature lattice quantum chromodynamics
This work determines the axion mass using lattice QCD, assuming that these particles are the dominant component of dark matter, and determines the universal axionic angle that corresponds to the initial condition of the authors' Universe. Expand
Hydrogen axion star: metallic hydrogen bound to a QCD axion BEC
A bstractAs a cold dark matter candidate, the QCD axion may form Bose-Einstein condensates, called axion stars, with masses around 10−11M⊙. In this paper, we point out that a brand new astrophysicalExpand
The QCD axion, precisely
A bstractWe show how several properties of the QCD axion can be extracted at high precision using only first principle QCD computations. By combining NLO results obtained in chiral perturbationExpand