Astronomers have revealed the strange behavior of the radio-loud magnetar Swift J1818.0-1607, which is a neutron star with an extremely strong magnetic field. Such objects are known as the strongest magnets in the universe.
The magnetar was detected in March 2020 by a powerful X-ray flash. After that, the object gave unusual radio pulses, which differed from those of other radio-loud magnetars. Usually radio pulses have constant brightness over a wide range of observed frequencies, however, the pulses from J18 are much brighter at low frequencies than at high frequencies, which makes it look like a pulsar.
In May, the magnetar was still emitting unusual pulsar-like pulses, but by June it began to flicker, fluctuating between pulsar-like and magnetic radio pulses. This behavior is unique and has not been observed before in any such object.