A Morphological Approach to the Pulsed Emission from Soft Gamma Repeaters

TL;DR

This paper introduces a geometrical method to interpret the periodic light curves of Soft Gamma Repeaters using a magnetar model and 3D magnetosphere simulations, explaining various emission morphologies and pulse profile evolution.

Contribution

It presents a novel geometrical approach combining magnetar theory and numerical magnetosphere modeling to explain SGR emission behaviors.

Findings

Explains burst tail and persistent stage morphologies via trapped fireballs.

Suggests pulse profile evolution is due to lateral drift of emission regions.

Provides numerical evidence linking magnetospheric dynamics to observed light curves.

Abstract

We present a geometrical methodology to interpret the periodical light curves of Soft Gamma Repeaters based on the magnetar model and the numerical arithmetic of the three-dimensional magnetosphere model for the young pulsars. The hot plasma released by the star quake is trapped in the magnetosphere and photons are emitted tangent to the local magnetic field lines. The variety of radiation morphologies in the burst tails and the persistent stages could be well explained by the trapped fireballs on different sites inside the closed field lines. Furthermore, our numerical results suggests that the pulse profile evolution of SGR 1806-20 during the 27 December 2004 giant flare is due to a lateral drift of the emitting region in the magnetosphere.