![]() The periodic nulling was initially reported in PSR B1133+16 (Herfindal & Rankin 2007, 2009), implying an association between subpulse drifting and nulling behavior. The pulse nulling is considered as a form of profile mode changing due to large-scale variations in the radio emission (Wang et al. Nevertheless, some peculiar pulsars exhibit various temporal variations in the pulse profile, showing no emission for a period of time (nulling), switching between one or more additional stable patterns of integrated profiles (mode switching or changing), or appearing as systematic subpulse drift motion through the pulse window (subpulse drifting). In most cases, the pulsed emission from every single rotation (thus individual or single pulses) is extremely variable in intensity, phase, shape, and polarization. The integrated pulse profiles constituted by averaging over tens of thousands of periods become highly stable for the majority of pulsars, and in most cases remain stable over several years at least. Pulsars are famous as highly magnetized and rapidly rotating neutron stars, providing us with an opportunity to explore physics under extreme conditions (Deng et al. Finally, possible physical mechanisms are discussed. The trailing component remains phase stationary within the pulse window but periodically modulates in amplitude with a period of three pulses. The leading component is modulated in longitude with a period of three pulses. The subpulse drifting is presented in the conal components and is absent in the central core emission. In addition to nulling, the pulsar also presents subpulse drifting in the single-pulse sequences with shorter periodicity. Additionally, the quasiperiodic modulations are significantly dependent on time. At 1369 MHz, the quasiperiodic nulling is detected, as well, to modulate across the entire profile both in the core and conal components simultaneously with a fluctuation rate of about 50 rotational periods, and the nulling fraction is estimated to be around 10%. About 12% nulls are found to create alternating bunches of nulls and bursts in a quasiperiodic manner with longer periodicities of 83, 28, and 14 rotational periods for simultaneous observations at 7 MHz. The single pulses show the presence of two distinct periodic modulations using fluctuation spectral analysis. The pulsar possesses three well-resolved emission components, with the central component resembling core emission. ![]() We have carried out a detailed study of single-pulse emission from the pulsar J2048−1616 (B2045−16), observed at 732, 1369, and 3100 MHz frequencies using the Parkes 64 m radio telescope.
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