SGR 0501+4516 is a soft gamma repeater (SGR), and is an ancient stellar remnant. Currently, the phenomenons of SGRs and the related Anomalous X-ray pulsars (AXP) are explained as arising from magnetars. SGR 0501+4516 is located approximately 15,000 light years from Earth and has a magnetic field 100 trillion times stronger than the Earth’s.
SGR 0501+4516 is remarkable in that it has been the first SGR to have been discovered after ten years without SGR detections. It has been suggested that SGR 0501+4516, together with 1E 1547.0-5408, should be considered as tools for a final unification of SGRs, AXPs and the “transient AXPs (TAXPs)” into a single class of “magnetars candidates”.
Discovery
Its existence has been reported on Aug. 22, 2008, by NASA's Swift satellite, which reported numerous blasts of radiation from the object. The eruptions has been subsequently in-depth studied using the European Space Agency's XMM-Newton and International Gamma-Ray Astrophysics Laboratory (INTEGRAL) satellites. The object had been serendipitously observed before in 1992 by ROSAT.