All Figures

Figure 1: Longitude-resolved ( a), left) and harmonic-resolved ( b), right) fluctuation spectra for pulsar B0809+74 at 328 MHz, computed using a WSRT PS recorded on 2000 Novermber 26. The analysis was applied to the total power (Stokes I) and used FFTs of length 512 and 256, respectively. The three panels of the left-hand LRF display give the pulsar's average profile ( left), LRF spectra ( centre), and integral spectrum, ( bottom) respectively; whereas, those of the right-hand HRF display give the (integer) harmonic amplitudes of the average profile ( left), the non-integer harmonic amplitudes associated with the modulation ( centre), and the integral fluctuation spectrum ( bottom). See DR01 for a complete description. The central panels of both displays use 8 contour levels; however, these cover only the lowest 5% of the feature amplitude of the HRF spectrum in order to exhibit the lowest level features. Note also that the longitude origin of the average profiles has been taken just above the half-power point on the profile's leading edge, following the analysis of Paper I.

Open with DEXTER


In the text

	Figure 2: Fluctuation-spectral phase and modulation amplitude at 328 MHz corresponding to the primary 0.092 c/P1 feature in Figs. 1a and b. Fluctuation power is plotted as a function of longitude within the average profile in the top panel, whereas the fluctuation phase is given in the lower panel.
Open with DEXTER


In the text

Figure 3: A total-power 34-beam polar cap "map'' of the accessible emission region reconstructed using the cartographic transform described in DR01. The image corresponds to the poleward or negative- solution in Paper I and maps the same bright 512-pulse section of the 328-MHz WSRT observation first studied in Fig. 1 (here beginning at pulse 135 so as to represent a single "carousel''-subbeam system rotation). The "drifting''-subpulse pattern is projected onto the magnetic polar cap shown in the main panel and its rotation frozen, with the "closer'' rotational axis at the top of the diagram and the sightline cutting the emission pattern near "12 o'clock''. The bottom and side panels show the average- and incoherent (non-accurately drifting) "base''-intensity profiles, respectively, as functions of the angular distance from the magnetic axis. The base intensity here has not been removed from the pattern in the central panel.

Open with DEXTER


In the text

Figure 4: ( Top) Composite 10-subbeam maps in total power and total-linear power (Stokes Q') of the same 328-MHz PS as in Figs. 1-3, here corresponding to the equatorward or positive- sightline solution in Paper I. The contours show the total power beam-system intensities ( left) as well as with the circularly symmetric "base'' function ( left panels) subtracted ( righthand figure). The color-intensity coding gives the respective linear polarization according to the scale at the right of the diagrams. The net polarization-modal power (PPM/SPM) is here distinguished only by the sign of Q': the positive (yellow-orange) modal "beamlets'' are more intense and fall on the inside of the diagram; whereas the negative (blue-cyan-green) beamlets occur further from the magnetic axis, fall off in a canted manner and are generally weaker. Here the sightline cuts the emission pattern from right to left at the bottom of the diagrams. The total power (solid curve) and residual linear (dotted) conal beam forms are shown in the bottom panels; the total power is truncated from a maximum value of about arbitrary units, whereas the linear shows the different radial dependences of the two polarization modes. Here, we have used pulses 179 to 512, corresponding to three putative circulation times for the 10-beam "carousel'' system. ( Below) Composite unpolarized (Stokes I- ) power (contours) and Q' (color scale) subbeam map. Here the "base'' has been subtracted, and the total power beamform ( bottom panel) truncated from a maximum value of about 104.

Open with DEXTER


In the text