Nano-Hz Gravitational-Wave Signature from Axion Dark Matter
Naoya Kitajima1,2, Jiro Soda3, Yuko Urakawa4,5
1Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Sendai 980-8578, Japan.
Abstract:
We calculate the accurate spectrum of the stochastic gravitational-wave background from U(1) gauge fields produced by axion dark matter. The explosive production of gauge fields soon invalidates the applicability of the linear analysis and one needs nonlinear schemes. We make use of numerical lattice simulations to properly follow the nonlinear dynamics such as backreaction and rescattering which gives important contributions to the emission of gravitational waves. It turns out that the axion with the decay constant f∼10^{16} GeV and the mass m∼10^{-14} eV which gives the correct dark matter abundance predicts the circularly polarized gravitational-wave signature detectable by SKA. We also show that the resulting gravitational-wave spectrum has a potential to explain NANOGrav 12.5 yr data.
More Related Videos
Related Concept Videos
Detection of Black Holes
Their closest cousins are neutron stars, which are composed almost entirely of neutrons packed against each other, making them extremely dense. A neutron star has the same mass as the Sun but its diameter is only a few kilometers. Therefore, the escape velocity from their surface is close to the speed of light.
Not until the 1960s, when the first neutron...
Atomic Nuclei: Larmor Precession Frequency
Schwarzschild Radius and Event Horizon
The minimum speed required to launch a projectile from the surface of an object to which it is gravitationally bound so that it eventually escapes the object’s gravitational field is called the escape velocity. The escape velocity is independent of the mass of the object. Merging the idea of escape...
The de Broglie Wavelength
Atomic Nuclei: Magnetic Resonance
¹H NMR Signal Multiplicity: Splitting Patterns


