Identification of the central compact object in the young supernova remnant 1E 0102.2–7219

Oxygen-rich young supernova remnants 1 are valuable objects for probing the outcome of nucleosynthetic processes in massive stars, as well as the physics of supernova explosions. Observed within a few thousand years after the supernova explosion 2 , these systems contain fast-moving oxygen-rich and hydrogen-poor filaments visible at optical wavelengths: fragments of the progenitor’s interior expelled at a few thousand kilometres per second during the supernova explosion. Here we report the identification of the compact object in the supernova remnant 1E 0102.2–7219 in reprocessed Chandra X-ray Observatory data, enabled by the discovery of a ring-shaped structure visible primarily in optical recombination lines of Ne i and O i . The optical ring has a radius of (2.10 ± 0.35)″ ≡ (0.63 ± 0.11) pc, and is expanding at a velocity of 90.5_-30^+40 km s −1 . It surrounds an X-ray point source with an intrinsic X-ray luminosity L i (1.2–2.0 keV) = (1.4 ± 0.2) × 10 33 erg s −1 . The energy distribution of the source indicates that this object is an isolated neutron star: a central compact object akin to those present in the Cas A 3 – 5 and Pup A 6 supernova remnants, and the first of its kind to be identified outside of our Galaxy.