Exploring the remarkable subpulse drift and polarization properties of PSR B0818-41

Abstract

PSR B0818-41 is one of the few pulsars which show multiple drift regions having well defined phase relationship. In this paper we report new results from the multifrequency GMRT observations of this pulsar. Significant linear polarization is observed with depolarization at the edge of the profile, due to orthogonal polarization. Circular polarization changes sign near the middle of the pulse profile at 1060 MHz, but not observed at 325 and 610 MHz. Remarkable frequency evolution of polarization angle (PA) is observed. Based on the frequency evolution of average profile, PA swing and results from subpulse drifting, we propose two possible emission geometries, alpha~11 deg, beta~-5.4 deg and alpha~175.4 deg, beta~-6.9 deg. Simulation of the pulsar radiation pattern with both these geometries reproduces the observed features in the drift pattern quite well. In addition to the remarkable subpulse drifting observed at 325 MHz, we report subpulse drifting at 244 and 610 MHz. We observe changes of drift rates, transitions from negative to stationary and stationary to negative drift rates, with some connection with nulls. Though P3m is the same for all the drift regions, P2m and Delta(Phi) values are different for the inner and outer drift regions. The peak emission from the leading and the trailing outer regions are offset by ~ 9 P1. Utilising this information, we solve the aliasing problem and predict P4~ 10 s, which makes it the fastest known carousel. The drift pattern from the two rings are phase locked for PSR B0818-41. The same is found to be true for, all pulsars showing drifting in multiple rings of emission and puts constraints on the theoretical models of pulsar emission mechanism and, favors a pan magnetospeheric radiation mechanism.

19 pages, 29 figures and 4 tables, Submitted to MNRAS

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Cited by in corpus (14)

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• Meterwavelength Single-pulse Polarimetric Emission Survey II: The phenomenon of Drifting Subpulses
• Classification of Subpulse Drifting in Pulsars
• Drifting, moding, and nulling: another look at pulsar B1918+19
• Low Frequency Observations of the Subpulse Drifter PSR J0034-0721 with the Murchison Widefield Array
• Investigation of the unique nulling properties of PSR B0818-41
• PSR J1926-0652: A Pulsar with Interesting Emission Properties Discovered at FAST
• Inter-relationship between the Two Emission Cones of B1237+25
• Explaining the subpulse drift velocity of pulsar magnetosphere within the space-charge limited flow model
• Linear-drifting sub-pulse sources in radio pulsars
• PSR J0026-1955: A curious case of evolutionary subpulse drifting and nulling
• Quasi-regular variations of subpulse drifting for PSR J1857+0057
• Expected imprints of the carousel in multi-frequency pulsar observations and new evidence for multi-altitude emission
• Testing the circularity of PSR B0818-41's carousel