SGR 0501+4516 is a

magnetar A magnetar is a type of neutron star with an extremely powerful magnetic field (~109 to 1011 T, ~1013 to 1015 G). The magnetic-field decay powers the emission of high-energy electromagnetic radiation, particularly X-rays and gamma rays.Ward; Br ...

that is a soft gamma repeater (SGR). Currently, the phenomena of SGRs and the related anomalous X-ray pulsars (AXP) are explained as arising from

s. 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 was reported on August 22, 2008, by NASA's Swift satellite, which reported numerous blasts of radiation from the object. The eruptions were subsequently studied in-depth using the

European Space Agency The European Space Agency (ESA) is a 23-member International organization, international organization devoted to space exploration. With its headquarters in Paris and a staff of around 2,547 people globally as of 2023, ESA was founded in 1975 ...

's XMM-Newton and International Gamma-Ray Astrophysics Laboratory (INTEGRAL) satellites. The object had been serendipitously observed before in 1992 by ROSAT. A study published in 2025 didn't find any

supernova A supernova (: supernovae or supernovas) is a powerful and luminous explosion of a star. A supernova occurs during the last stellar evolution, evolutionary stages of a massive star, or when a white dwarf is triggered into runaway nuclear fusion ...

remnants within the area that SGR 0501+4516 had traversed during its expected lifetime. It concluded that some magnetars might be significantly older than expected, or that their progenitors produce low supernova ejecta masses, or that they can be formed by accretion-induced collapse or low-mass neutron star mergers.

References

Auriga Magnetars Soft gamma repeaters {{var-star-stub