stecf.impol - an IRAF Imaging Polarimetry Reduction Package

The impol package consists of five tasks to reduce, simulate and plot imaging linear polarimetry data taken with the HST instruments with polarizing facilities - currently FOC, NICMOS and WFPC2. The tasks are written to require minimum user interaction so that specialist knowledge is not required to produce scientifically useful polarization results. Starting from well-aligned input images, along with statistical error maps, images of the total signal (Stokes parameter I), the normalized Stokes parameters Q/I and U/I, the linear polarization and position angle of the E vector and their propagated errors are produced.

 

Figure: An example of the output from stecf.impol showing polarization vectors plotted on an HST WFPC2 F673N filter image of the Homunculus nebula surrounding $\eta$ Carinæ.