Pulsars are one of the most accurate timekeepers in the universe. They send out distinctly repetitive emissions over their rotation period which can be as short as 0.001 seconds. These emissions are observed by us as lightcurves but lightcurves show only the intensity of the emission reaching us. Light has a complex nature and requires 4 distinct parameters to characterise it completely - the 4 stokes parameters.
Shown in this animation is the first ever simulation of these 4 stokes parameters in the optical band for a rapidly rotating neutron star. The specific neutron star is the Crab pulsar (PSR B0531+21) - rotation period = 0.0334s. The two plots on the leftmost side show (as a surface) how the intensity (or lightcurve) varies for observers positioned at different points in space - represented by the viewing angle or "view" as pointed out on the animation. The 4 rightmost plots show the stokes Q versus U parameters, the lightcurve, polarisation angle and percentage polarisation respectiely as one moves in an anti-clockwise direction from the top rightmost plot.
The images on the left represent the correponding "difference image". The difference image is created by obtaining the convolution kernel required to match in seeing (and intensity) an arbitrary reference frame to each individual exposure. Each resultant matched reference image is then subtracted from each individual exposure. Any intensity variations between the image in question and the reference manifest themselves as intensity variations in the difference image.
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