Black widow pulsar systems are usually characterized by ablating the companion by pulsar emissions. They got their name from the “black widow” spiders. These systems give crucial insights into the characteristics of the companion stars under intense irradiation.
Using the Five-hundred-meter Aperture Spherical radio Telescope (FAST), a research team led by Dr. WANG Shuangqiang from the Xinjiang Astronomical Observatory (XAO) of the Chinese Academy of Sciences discovered plasma lensing phenomenon in a black widow pulsar PSR J1720-0533.
Scientists found that the emission of PSR J1720-0533 during the ingress of the eclipse shows quasi-periodic modulations, which may be caused by plasma lensing.
By analyzing the lensing phenomenon, scientists concluded that the maximum magnification for the lens is 1.6, corresponding to a lens size of tens of kilometers. The discovery of the plasma lensing phenomenon in PSR J1720-0533 demonstrates a link between the dispersion measurement and lensing.
When scientists examined the polarization profiles near the eclipse of PSR J1720-0533, scientists found that the linear polarization of the emission disappeared before the dispersion measurement showed significant changes. This phenomenon provides strong evidence that the companion has a strong magnetic field.
These results suggest that magnetic fields play an essential role in the eclipsing mechanism of black widow pulsars. Scientists also estimated that the companion’s mass-loss rate is 10-12 M⊙/yr. It is speculated that the companion will be destroyed entirely in 1010 yr.
- S. Q. Wang et al. Unusual Emission Variations Near the Eclipse of Black Widow Pulsar PSR J1720−0533. DOI: 10.3847/2041-8213/ac365c