Figure 1: Examples of Stokes V profiles. Solid: measured profiles; dashed: double Gaussian fit to the data; dash-dotted: from Eq. (3) with appropriate . | |
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Figure 2: Example of PFe at , sections of speckle reconstructed broadband image ( upper) and relevant magnetogram ( lower), obtained with the centre of gravity method. Dark and light shades in the magnetogram refer to negative and positive magnetic polarity, respectively. The minimum effective field strength is -230 G, the maximum is +120 G. Only fields with G have entered the magnetogram. Circles indicate areas with bright features but no significant magnetic flux ( lower left), and areas with significant flux, but without substantial brightness ( upper right). The arrow points towards the limb. | |
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Figure 3: Contrast C of PFe and of granules vs. . The asterisks give the mean contrast of PFe within one FOV and the error bars represent the standard deviation of facular contrast within the same FOV. The dashed straight lines are linear fits to the facular contrast. The crosses show twice the rms contrast of granules in the FOVs with no (or little) magnetic flux, (see text). The dotted straight line is a least square fit to the granular contrast. | |
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Figure 4: Distributions of PF areas determined with the COG method, i.e. from the number of pixels covered by the magnetic field of the PFe, for the northern polar cap ( left two panels) and the southern cap ( right two panels). The areas are corrected for foreshortening (dividing by ). The dashed vertical line in the upper left panel indicates the area of a circular PFe with 1 diameter. | |
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Figure 5: Variation towards the limb of PF magnetic field strengths measured with the COG method. The asterisks represent averages from each PF. The straight dashed line gives representing a hypothetical limb variation of the COG measurement for a purely vertical and constant flux density of G. | |
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Figure 6: Histogram of magnetic field strengths from the separation of Stokes V extrema. The solid lines correspond to the northern PFe and the dashed lines to the southern PFe. | |
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Figure 7: Variation towards the limb of velocities in PFe measured with the COG method from Stokes I profiles. Asterisks represent the mean velocity of PFe for each FOV and the error bars are the standard deviation of facular velocities within the same FOV. Reference zero velocity (horizontal dashed line) is the average of all line positions (from COG) in the corresponding FOVs. The dotted line is a linear regression. Positive velocities are away from the observer. | |
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Figure 8: Velocities measured from Doppler shift of Stokes I COG and from V zero-crossing. Reference zero velocity is the average of the line positions in the FOVs. Vertical dotted lines indicate the average velocities. Positive velocities are away from the observer. | |
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