The spectrum of pulsars is usually power-law, and pulsars are usually highly polarized. The shape and width of the average pulse profile mainly change with frequencies. Studying the emission intensity, polarization and spectrum of pulse profiles could help to better understand the structure of the emission region.

ZHOU Zurong, a PhD student from the Pulsar Research Group of the Xinjiang Astronomical Observatory (XAO) of the Chinese Academy of Sciences (CAS), and her co-researchers studied the first flux density measurements, spectral indices, pulse profiles, and correlations of the spectral index with pulsar parameters for 19 pulsars employing the Ultra-Wideband Low frequency (UWL) receiver system installed on the Parkes radio telescope.

The results showed that the pulsar evolution characteristics of flux densities, pulse widths, and polarizations with frequency, which deepens understanding of pulsar radiation region structure.

The study was published in Research in Astronomy and Astrophysics (RAA, 2022, 22085001).

The researchers divided the UWL data sets into three sub-bands and measure the flux density for each of them. The spectral behaviour of the 17 pulsars can be well described by a simple power？law over the frequency range considered, and the results for spectral indices of 17 pulsars are in the range between -3.10 and -0.6. For PSR J1810-5338, a broken power law is a batter to describe the spectrum with 600 MHz of cut-off frequency. For the first time, the researchers measured the polarization profiles of 13 pulsars at the center frequencies of 1369 or 2368 MHz, and found direct evidence that some pulsars may have evolved in frequency, as shown in Figure 1.