Anomalous X-ray pulsars (AXPs) are thought to be magnetars which are young isolated neutron stars with extremely strongmagnetic fields of >1014 Gauss. Their tremendous magnetic fields inferred from the spin parameters provide a huge energyreservoir to power the observed X-ray emission. High-energy emission above 0.3 MeV has never been detected despiteintensive search. Here, we present the possible Fermi Large Area Telescope (LAT) detection of γ-ray pulsations above 200MeV from the AXP, 1E 2259+586, which puts the current theoretical models of γ-ray emission mechanisms of magnetars intochallenge. We speculate that the high-energy γ-rays originate from the outer magnetosphere of the magnetar.

• Wu, Jason Hung Kit
• Hui, Chung Yue | Hui, Chung Yue
• Huang, Regina Hsiu Hui | Huang, Regina Hsiu Hui
• Kong, Albert Kwok Hing | Kong, Albert Kwok Hing
• Cheng, Kwong Sang | Cheng, Kwong Sang
• Takata, Jumpei | Takata, Jumpei
• Tam, Pak Hin Thomas | Tam, Pak Hin Thomas
• Wu, Eric Man Ho | Wu, Eric Man Ho
• Liu, Joe | Liu, Joe