(ORDO NEWS) — Astronomers analyzing data from the VLA Sky Survey have discovered one of the youngest known neutron stars, the superdense remnant of a massive star that exploded in a supernova.
Images from the National Science Foundation’s Carl G. Jansky Very Large Array (VLA) show that the bright radio emission from the spinning pulsar’s magnetic field has only recently emerged from a dense shell of supernova debris.
The object, named VT 1137-0337, is located in a dwarf galaxy at a distance of 395 million light years from Earth. It first appeared in a VLA image taken in January 2018 and continued to flicker in 2018, 2019, 2020 and 2022.
“We are most likely seeing a pulsar wind nebula,” says Dillon Dong of the National Radio Astronomy Observatory. The Pulsar Wind Nebula is formed when the powerful magnetic field of a rapidly spinning neutron star accelerates surrounding charged particles to nearly the speed of light.
“Judging by the characteristics, this is a very young pulsar – perhaps only 14 years old, but no more than 60-80.”
“This object is notable for the fact that its galaxy is experiencing a burst of star formation, as well as the characteristics of its radio emission,” Dong said. The galaxy, named SDSS J113706.18-033737.1, is a dwarf galaxy with a mass about 100 million times that of the Sun.
In studying the characteristics of VT 1137-0337, astronomers considered several possible explanations, including a supernova, a gamma-ray burst, or a tidal decay event in which a star is destroyed by a supermassive black hole. They concluded that the best explanation is the pulsar wind nebula.
In this scenario, a star much more massive than the Sun exploded as a supernova, leaving behind a neutron star. Much of the mass of the original star was thrown outward as a shell of debris. A neutron star spins rapidly, and as its powerful magnetic field sweeps through its surroundings, it accelerates charged particles, causing strong radio emission.
Initially, the radio emission was blocked by a shell of debris from the explosion. As this shell expanded, it became less and less dense, until eventually radio waves from the pulsar’s wind nebula could not pass through it.
While scientists consider VT 1137-0337 the most likely pulsar wind nebula, it is possible that its magnetic field could be strong enough to qualify a neutron star as a magnetar, a class of supermagnetic objects.
“In that case, this would be the first magnetar caught at the time of occurrence, and this is also extremely interesting,” Dong concluded.
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