Using observations across the entire electro-magnetic spectrum, astronomers have discovered a radio pulsar spinning 707 times every second, making it the fastest known spinning pulsar in the Galactic field and the second fastest known overall.

The pulsar emits pulsed electromagnetic radiation at very low radio frequencies and very high gamma-rays, while the low-mass binary companion, heated by the energetic radiation from the pulsar, is detected at optical wavelengths. The discovery of this system at very low radio frequencies suggests there may be an as yet unseen population of fast spinning radio pulsars.

The pulsar, PSR J0952-0607, was discovered with LOFAR, the Low-Frequency Array, a radio telescope consisting of a dense core of antenna stations in the Netherlands, and international stations in Germany, France, Sweden, the United Kingdom, Sweden, Poland and Ireland. Operating at very low radio frequencies of 110 to 150 MHz, the LOFAR telescope targeted unassociated high-energy gamma-ray sources discovered with the space-based Fermi gamma-ray telescope, searching for pulsed radio emission of radio and gamma-ray bright millisecond pulsars.

Radio observations revealed that PSR J0952-0607 is part of a binary system, where the pulsar orbits a very low mass (2% the mass of the Sun) binary companion every 6.42 hours. In these so-called 'black widow' systems, referencing the spider which consumes its mate, the proximity of the companion to the pulsar meant the hemisphere facing the pulsar is heated by the energetic pulsar emission, leading to the evaporation of matter from the companion. This heating leads to large variations in brightness of the companion over the course of an orbit.