An alternative interpretation of magnetars' traits deduced from the observational data on their outburst fluxes and spectra

TL;DR

This paper proposes a new interpretation of magnetar observational data, suggesting their X-ray luminosities are consistent with spin-down luminosities and their spectra align with pulsar-like emission mechanisms, supported by statistical analysis.

Contribution

It introduces an alternative model for magnetar emissions based on the dependence of flux on distance and spectral energy distribution, challenging prevailing views.

Findings

Flux dependence is consistent with $S\propto D^{-3/2}$, not $D^{-2}$.

Magnetar X-ray luminosities do not exceed spin-down luminosities.

Magnetar spectra match the broadband non-thermal emission seen in pulsars.

Abstract

By applying the Efron-Petrosian method to the fluxes $S$ and distances $D$ of the magnetars listed in the Magnetar Outburst Online Catalogue, we show that the observational data are consistent with the dependence $S\propto D^{-3/2}$, which characterizes the emission from the superluminally moving current sheet in the magnetosphere of a non-aligned neutron star, at substantially higher levels of significance than they are with the dependence $S\propto D^{-2}$. This result agrees with that previously obtained by an analysis of the data in the McGill Online Magnetar Catalog and confirms that, contrary to the currently prevalent view, magnetars' X-ray luminosities do not exceed their spin-down luminosities. The X-ray spectra of magnetars, moreover, are congruous with the spectral energy distribution (SED) of a broadband non-thermal emission mechanism identical to that at play in rotation-powered pulsars: we show that the SED of the caustics that are generated in certain privileged directions by the magnetospheric current sheet single-handedly fits the observed spectra of 4U 0142+61, 1E 1841-045 and XTE J1810-197 over their entire breadths. Magnetars' outbursts and their associated radio bursts are predicted to occur when, as a result of large-scale timing anomalies (such as glitches, quakes or precession), one of the privileged directions along which the radiation from the current sheet decays more slowly than predicted by the inverse-square law either swings past or oscillates across the line of sight.