Andromeda's pulsing neutron star
Andromeda, or M31, is a spiral galaxy similar to our own Milky Way. For the first time, a spinning neutron star has been inferred in XMM-Newton data.
Inset: Light curve of the source, known as 3XMM J004301.4+413017, as analysed by XMM-Newton's European Photon Imaging Camera, EPIC. The source has a period of 1.2 seconds, consistent with a spinning neutron star.