NASA's NICER finds X-ray boosts in the Crab Pulsar's radio bursts
A global science collaboration using data from NASA’s Neutron star Interior Composition Explorer (NICER) telescope on the International Space Station has discovered X-ray surges accompanying radio bursts from the pulsar in the Crab Nebula. The finding shows that these bursts, called giant radio pulses, release far more energy than previously suspected.
A pulsar is a type of rapidly spinning neutron star, the crushed, city-sized core of a star that exploded as a supernova. A young, isolated neutron star can spin dozens of times each second, and its whirling magnetic field powers beams of radio waves, visible light, X-rays, and gamma rays. If these beams sweep past Earth, astronomers observe clock-like pulses of emission and classify the object as a pulsar.
“Out of more than 2,800 pulsars cataloged, the Crab pulsar is one of only a few that emit giant radio pulses, which occur sporadically and can be hundreds to thousands of times brighter than the regular pulses,” said lead scientist Teruaki Enoto at the RIKEN Cluster for Pioneering Research in Wako, Saitama prefecture, Japan. “After decades of observations, only the Crab has been shown to enhance its giant radio pulses with emission from other parts of the spectrum.”
The new study, which will appear in the April 9 edition of Science and is now available online, analyzed the largest amount of simultaneous X-ray and radio data ever collected from a pulsar. It extends the observed energy range associated with this enhancement phenomenon by thousands of times.
Located about 6,500 light-years away in the constellation Taurus, the Crab Nebula and its pulsar formed in a supernova whose light reached Earth in July 1054. The neutron star spins 30 times each second, and at X-ray and radio wavelengths it is among the brightest pulsars in the sky.
Between August 2017 and August 2019, Enoto and his colleagues used NICER to repeatedly observe the Crab pulsar in X-rays with energies up to 10,000 electron volts, or thousands of times that of visible light. While NICER was watching, the team also studied the object using at least one of two ground-based radio telescopes in Japan — the 34-meter dish at the Kashima Space Technology Center and the 64-meter dish at the Japan Aerospace Exploration Agency’s Usuda Deep Space Center, both operating at a frequency of 2 gigahertz.
