Comparing Hertz and SHARP results for the central 20" of M82. The Hertz result for M82 is 1.0 % at 80 degrees This is for a position that is within a few arcsec (about 3" E, 2" N) of the submillimeter centroid of M82. This is a 3-sigma result (barely). I was curious to see how this might compare with the SHARP result, so I attempted to do my own crude average of John's recent results for M82. I had to include the low-polarization parts of M82 in the average, not only the 2-sigma detections, so I used his map from May 15th, that shows all data points regardless of the significance. Since most points are for regions where the flux is much lower than the peak, I used only four points in the average: - the central point, for which I estimate 1.2% at 75 degrees - the point just to the West, for which I estimate 0.6% at 110 degrees - the point just to the East, for which I estimate 1.5% at 50 degrees - the point one step to the East and one step to the North, for which I get 2.0% at 75 degrees The separation between the points is about 10 arcsec, so all these positions contribute to the flux measured by Hertz. Since the latter two points have significantly lower flux, judging from the grey-scale map, I gave them half the weight of the first two points. The Stokes' parameters for the four points are, respectively (in percent): q u -1.04 +0.60 -0.46 -0.39 -0.26 +1.48 -0.35 +1.97 And the weighted average is: -0.60 +0.65 _________ Comparision of the two instruments' results: instrument: Hertz SHARP P: 1.0 0.9 Phi: 80 67 q: -0.94 -0.60 u: +0.34 +0.65 The errors in q, u, and P are about 0.3% for Hertz One could make an estimate of the errors in the SHARP result by propagating errors, but I have not tried this. ________