Slowest-spinning radio pulsar investigated by scientists

September 12, 2021

Using ground-based facilities, an international team of astronomers has conducted a broadband radio study of a slowly rotating radio pulsar known as PSR J0250+5854. Results of this investigation provide more insights into the nature of this source.

Radio pulsars are generally described as highly magnetized, rapidly rotating neutron stars with a lighthouse beam of radiation that produces the pulsed emission.

With a period of 23.5 seconds, PSR J0250+5854 is the slowest-spinning radio pulsar known to date. Previous observations have shown that PSR J0250+5854 has an extremely large light-cylinder (with a radius of about 1.12 million kilometers) and a tiny polar cap (with an estimated diameter of some 60 meters).

The study found that PSR J0250+5854 has a flux density of 4.0 µJy at 1250 MHz and a spectral index of approximately −3.5, with a turnover below 95 MHz. It was noted that the spectral index is exceptionally steep when compared to the mean found for the pulsar population—between -1.6 and -1.4.

Furthermore, the pulse profile of PSR J0250+5854 shows narrowing at lower frequencies, contrary to the expectations of radius-to-frequency mapping. It was also found that the pulsar's polar cap radio emission is produced at an absolute height of several hundreds of kilometers around 1.5 GHz.

S - https://phys.org/news/2021-09-pulsar-psr-j02505854.html