Pulsed {\gamma}-ray emission from magnetar 1E 2259+586

TL;DR

This paper reports the potential detection of high-energy gamma-ray pulsations from the magnetar 1E 2259+586, challenging existing models of gamma-ray emission in magnetars and suggesting an origin in the outer magnetosphere.

Contribution

It presents the first possible detection of gamma-ray pulsations above 200 MeV from a magnetar, providing new insights into magnetar emission mechanisms.

Findings

Possible gamma-ray pulsations detected above 200 MeV from 1E 2259+586

Detection challenges existing gamma-ray emission models for magnetars

High-energy gamma-rays may originate from the outer magnetosphere

Abstract

Anomalous x-ray pulsars (AXPs) are thought to be magnetars which are young isolated neutron stars with extremely strong magnetic fields of > 10^14Gauss. Their tremendous magnetic fields inferred from the spin parameters provide a huge energy reservoir to power the observed x-ray emission. High-energy emission above 0.3 MeV has never been detected despite intensive search. Here, we present the possible Fermi Large Area Telescope (LAT) detection of {\gamma}-ray pulsations above 200 MeV from the AXP, 1E 2259+586, which puts the current theoretical models of {\gamma}-ray emission mechanisms of magnetars into challenge. We speculate that the high-energy {\gamma}-rays originate from the outer magnetosphere of the magnetar.