2024ApJ...968..119X

Careful scrutiny of the single pulse emissions from PSR B2110+27 has been conducted through highly sensitive observations using the Five-hundred-meter Aperture Spherical radio Telescope (FAST) at a central frequency of 1250 MHz. Our investigation revealed significant subpulse drift behavior and nulling in this pulsar. Moreover, we observed that the nulling events tend to be of short duration, with an estimated overall nulling fraction of approximately 27% ± 3%. It is noteworthy that the drift direction of the subpulses exhibits abrupt changes, occasionally transitioning into a steady state or displaying a low drift rate. Analysis using longitude resolved fluctuation spectra indicates the presence of two distinct repetition periods for the pulsar: P₃ = (10.8 ± 2.5)P and P₃ = (31.6 ± 4.2)P, where P denotes the pulsar period. Our investigation revealed that the subpulse separation remains consistent across different drift patterns, with P₂ = 2.°3 ± 0.°2. A more comprehensive analysis indicates that the unique drift behavior observed can be explained by a carousel model of the dipole field. Minor changes in P₂ and drift rate caused significant variations in the apparent P₃ and abrupt shifts in the drift direction, while the true repetition period (assuming first-order aliasing) changed by only ∼10%. We observe a drift band memory and apparent phase memory across the null state in this pulsar, as well as variations in the drift rate and drift direction across the null state, though we have not detected significant periodicity of the nulling itself. This suggests that these phenomena may arise from random null pulses intersecting with the frequently aliased drift bands.