The Geometry of PSR B0031-07

Abstract

PSR B0031-07 is well known to exhibit three different modes of drifting sub-pulses (mode A, B and C). It has recently been shown that in a multifrequency observation, consisting of 2700 pulses, all driftmodes were visible at low frequencies, while at 4.85 GHz only mode-A drift or non-drifting emission was detected. This suggests that modes A and B are emitted in sub-beams, rotating at a fixed distance from the magnetic axis, with the mode-B sub-beams being closer to the magnetic axis than the mode-A sub-beams. Diffuse emission between the sub-beams can account for the non-drifting emission. Using the results of an analysis of simultaneous multifrequency observations of PSR B0031-07, we set out to construct a geometrical model that includes emission from both sub-beams and diffuse emission and describes the regions of the radio emission of PSR B0031-07 at each emission frequency for driftmodes A and B. Based on the vertical spacing between driftbands, we have determined the driftmode of each sequence of drift. To restrict the model, we calculated average polarisation and intensity characteristics for each driftmode and at each frequency. The model reproduces the observed polarisation and intensity characteristics, suggesting that diffuse emission plays an important role in the emission properties of PSR B0031-07. The model further suggests that the emission heights of this pulsar range from a few kilometers to a little over 10 kilometers above the pulsar surface. We also find that the relationships between height and frequency of emission that follow from curvature radiation and from plasma-frequency emission could not be used to reproduce the observed frequency dependence of the width of the average intensity profiles.

15 pages, 9 figures, 8 tables, accepted for publication in A&A

References in corpus (7)

• Understanding the radio emission geometry of PSR B0329+54
• Toward An Empirical Theory of Pulsar Emission. VII. On the Spectral Behavior of Conal Beam Radii and Emission Heights
• Comparing Geometrical and Delay Radio Emission Heights in Pulsars
• Pulsar Radio Emission Altitude from Curvature Radiation
• Frequency dependence of the drifting subpulses of PSR B0031-07
• Ellipticity and Deviations from Orthogonality in the Polarization Modes of PSR B0329+54
• Competing Drifting Radio Subpulses in PSR B0031-07

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• A low frequency study of PSRs B1133+16, B1112+50, and B0031-07
• The frequency-dependent behaviour of subpulse drifting: I. Carousel geometry and emission heights of PSR B0031-07
• S2DFS: Analysis of temporal changes of drifting subpulses
• Simultaneous multi-frequency single pulse observations of pulsars
• Results from multi-frequency observations of PSR B0826-34
• Variations of $P_2$ in subpulse drifting pulsars
• Andromeda IV, a solitary gas-rich dwarf galaxy
• A short review of the pulsar magnetic inclination angles (II)
• Properties of the emission region in pulsars with opposite subpulse drift directions in different profile components