FAST Observations of the Microstructure in Interpulse Pulsars

Abstract In this study, we investigate the microstructure properties of four pulsars (PSRs J0953+0755 (B0950+08), J0627+0706, J0826+2637 (B0823+26), and J1946+1805 (B1944+17)) using the Five-hundred-meter Aperture Spherical radio Telescope, with particular emphasis on identifying microstructure within the interpulse (IP). Through the application of autocorrelation function analysis and fast Fourier transform techniques, we have systematically examined the periodicity of microstructure in these pulsars. Our findings represent the first successful detection of microstructure within the IP. Furthermore, we conducted a comprehensive statistical analysis comparing the characteristic timescales ( τ μ ) and the characteristic periods P μ of quasiperiodic microstructure between the main pulse (MP) and the IP, and our results indicate that the τ μ and P μ of microstructure across components appear consistent within measurement errors for PSR J0627+0706, but the microstructure in the IP is relatively smaller than that in the MP for PSR J0953+0755. Furthermore, the relationship between P μ of microstructure and the rotation period in neutron star populations was reconfirmed: P μ (ms) = (1.337 ± 0.114) × P (s) (1.063±0.038) .