Investigation of Periodic Modulation Behaviors from Pulsar J2022+5154

We have carried out a detailed study of individual pulse emission from the pulsar J2022+5154 (B2021+51), observed at 2250 MHz using the Jiamusi 66 m radio telescope. We have investigated the modulations in single-pulse behavior using fluctuation spectral analysis, which shows the presence of two prominent periodicities, around 5 and 40 rotation periods, respectively. The shorter periodicity is associated with the phenomenon of subpulse drifting. In the absence of aliasing, the emission pattern is demonstrated to consist of eight subbeams, which rotate around the magnetic axis in about 45 periods. In addition to subpulse drifting, the pulsar also shows the presence of periodic amplitude modulation with a longer periodicity in the single-pulse sequence. The pulsar joins a select group that shows the presence of periodic phase-modulated drifting as well as amplitude-modulated drifting. This provides further evidence for the two phenomena being distinct from each other with different physical origins.