A large sample of pulsars was observed as part of the Meterwavelength Single-pulse Polarimetric Emission Survey. We carried out a detailed fluctuation spectral analysis that revealed periodic features in 46% of pulsars, including 22 pulsars where drifting characteristics were reported for the first time. The pulsar population can be categorized into three distinct groups: pulsars that show systematic drift motion within the pulse window, pulsars showing no systematic drift but periodic amplitude fluctuation, and pulsars with no periodic variations. We discovered the dependence of the drifting phenomenon on the spin-down energy loss ( E ˙ ), with the three categories occupying distinctly different regions along the E ˙ axis. The estimation of the drift periodicity (P ₃) from the peak frequency in the fluctuation spectra is ambiguous due to the aliasing effect. However, using basic physical arguments we were able to determine P ₃ in pulsars showing systematic drift motion. The estimated P ₃ values in these pulsars were anti-correlated with E ˙ , which favored the partially screened gap model of the inner acceleration region in pulsars.

We have conducted the Meterwavelength Single-pulse Polarimetric Emission Survey to study the radio emission properties of normal pulsars. A total of 123 pulsars with periods between 0.1 and 8.5 s were observed in the survey at two different frequencies: 105 profiles at 333 MHz, 118 profiles at 618 MHz, and 100 pulsars at both. In this work we concentrate primarily on the time-averaged properties of the pulsar emission. The measured widths of the pulsar profiles in our sample usually exhibit the radius-to-frequency mapping. We validate the existence of lower bounds for the distribution of profile widths with pulsar period (P), which is seen for multiple definitions of the width, namely, a lower boundary line (LBL) at 2.°7P ^−0.5 with width measured at 50% level of profile peak, an LBL at 5.°7 P ^−0.5 for 10% level of peak, and an LBL at 6.°3P ^−0.5 for width defined as 5σ above the baseline level. In addition, we have measured the degree of linear polarization in the average profile of pulsars and confirmed their dependence on pulsar spin-down energy loss ( E ˙ ). The single-pulse polarization data show interesting trends, with the polarization position angle (PPA) distribution exhibiting the simple rotating vector model for high- E ˙ pulsars, while the PPA becomes more complex for medium- and low- E ˙ pulsars. The single-pulse total intensity data are useful for studying a number of emission properties from pulsars like subpulse drifting, nulling, and mode changing, which are being explored in separate works.

Periodic modulations are seen in normal pulsars (P > 0.1 s) over timescales ranging from a few seconds to several minutes. Such modulations have usually been associated with the phenomenon of subpulse drifting. A number of recent studies have shown subpulse drifting to exhibit very specific physical characteristics: (i) drifting is seen only in conal components of the pulse profile and is absent in central core emission; (ii) drifting pulsars are distributed over a narrow range of spin-down energy loss ( ), where pulsars with 2 × 10³² erg s⁻¹ show this behavior; and (iii) drifting periodicity (P ₃) is anti-correlated with , such that pulsars with lower values of tend to have longer P ₃. These detailed characterizations of drifting behavior, on the other hand, also revealed the presence of other distinct periodic modulations, which can be broadly categorized into two types, periodic nulling, and periodic amplitude modulation. In contrast to drifting, these periodic phenomena are seen across the entire profile in both the core and conal components simultaneously and are not restricted to any specific range. In this work we have assembled an exhaustive list of around 70 pulsars that show such periodic modulations, 22 of which were newly detected using observations from the Giant Meterwave Radio Telescope and the remaining compiled from past publications. The presence of such a significant group in the pulsar population suggests periodic modulations to be newly emergent phenomena in pulsars, with a physical origin that is distinct from that of subpulse drifting.

We report a detailed observational study of the single pulses from the pulsar J1822−2256. The pulsar shows the presence of subpulse drifting, nulling as well as multiple emission modes. During these observations the pulsar existed primarily in two modes; mode A with prominent drift bands and mode B which was more disorderly without any clear subpulse drifting. A third mode C was also seen for a short duration with a different drifting periodicity compared to mode A. The nulls were present throughout the observations but were more frequent during the disorderly B mode. The nulling also exhibited periodicity with a clear peak in the fluctuation spectra. Before the transition from mode A to nulling the pulsar switched to a third drifting state with periodicity different from both mode A and C. The diversity seen in the single pulse behaviour from the pulsar J1822−2256 provides an unique window into the emission physics.

We report on simultaneous X-ray and radio observations of the radio-mode-switching pulsar PSR B1822−09 with ESA's XMM–Newton and the Westerbork Synthesis Radio Telescope, Giant Metrewave Radio Telescope and Lovell radio telescopes. PSR B1822−09 switches between a radio-bright and radio-quiet mode, and we discovered a relationship between the durations of its modes and a known underlying radio-modulation time-scale within the modes. We discovered X-ray (energies 0.2–1.4 keV) pulsations with a broad sinusoidal pulse, slightly lagging the radio main pulse in phase by 0.094 ± 0.017, with an energy-dependent pulsed fraction varying from ∼0.15 at 0.3 keV to ∼0.6 at 1 keV. No evidence is found for simultaneous X-ray and radio mode switching. The total X-ray spectrum consists of a cool component (T ∼0.96 × 10⁶ K, hotspot radius R ∼2.0 km) and a hot component (T ∼2.2 × 10⁶ K, R ∼100 m). The hot component can be ascribed to the pulsed emission and the cool component to the unpulsed emission. The high-energy characteristics of PSR B1822−09 resemble those of middle-aged pulsars such as PSR B0656+14, PSR B1055−52 and Geminga, including an indication for pulsed high-energy gamma-ray emission in Fermi Large Area Telescope data. Explanations for the high pulsed fraction seem to require different temperatures at the two poles of this orthogonal rotator, or magnetic anisotropic beaming effects in its strong magnetic field. In our X-ray skymap, we found a harder source at only 5.1 ± 0.5 arcsec from PSR B1822−09, which might be a pulsar wind nebula.