Pulsed {\gamma}-ray emission from magnetar 1E 2259+586
  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. 
J. H. K. Wu, C. Y. Hui, R. H. H. Huang, A. K. H. Kong, K. S. Cheng, J.   Takata, P. H. T. Tam, E. M. H. Wu and C.-Y. Liu
astro-ph.HE