Superdense beaming of axion dark matter in the vicinity of the light cylinder of pulsars

Abstract

In this article we treat the non-adiabatic resonant photon-to-axion conversion of curvature radiation, synchrotron emission and inverse Compton scattering dominating the spectral density function of pulsars. First, we introduce state-of-the-art emission models and reference observational data. Relying on recurring idealizations in the literature, we derive an analytical expression that allows one to estimate the photon-axion oscillation probability across the light cylinder of the neutron star. Then, we estimate the dark matter flux induced by photon-to-axion conversion. We find that pulsars might produce axion overdensities many orders of magnitude over the occupation number of dark matter in the Galactic halo within a broad parameter space. We discuss axion-astronomy prospects and heterogeneous future lines.

Axion-photon multimessenger astronomy with giant flares

“…In the standard picture, their persistent emission mechanisms involve pair production and magnetic acceleration, catalyzing the migration of charges to higher altitudes from the neutron star to give raise to curvature radiation, synchrotron emission and inverse Compton scattering [11,12]. The beamed photons could be converted to axion through non-adiabatic resonant mechanism at their path across the 'cold' plasma of the magnetosphere [13][14][15][16][17][18]. In the aligned-rotator approximation, where the magnetic axis and the rotation axisẑ -are superimposed, the axion-photon oscillation amplitude is derived from introducing the resonance condition ∆ p − ∆ φ = 0 in Eq.…”