Anton Pannekoek Institute for Astronomy

Bizarre pulsar drives an ultraluminous x-ray source

28 February 2017

An international team of scientists, among Paolo Esposito of the Anton Pannekoek Instituut for Astronomy, describes the discovery of a special pulsar that created an Ultra luminous X-ray source in a Science article that is published on 24 February.

An Ultra luminous X-ray source (ULX) in the splinter galaxy, NGC5907, is particularly bright even among ULXs and while this seemed to point to the presence of an unusually massive black hole, it now appears to be caused by a strange kind of pulsar.

Violent phenomena

Normally, an accreting pulsar would not be as bright as a black hole, but by adding a strong multipolar magnetic field, the group led by Gian Luca Israel, has proposed a solution for the object’s extreme luminosity. Ultraluminous x-ray sources (ULXs) in nearby galaxies shine brighter than the x-ray sources in our own galaxy. This suggests that they are caused by extremely violent phenomena and thus far, black holes were seen as the causes of these bright sources.

This new explanation for the brightness of the x-ray source in NGC5907 suggests that other extreme ULXs might also be caused by neutron stars.

NGC 5907 with annotated ULXs-API-2017

NGC 5907 with annotated ULXs. The pulsar is highlighted.

Published by  Faculty of Science