Abstract

The second sentence in each of the captions of Figures 2 and 3 of the published article should be "Light blue ribbons show the 1σ scatter at each radial bin divided by the square root of the number of beams spanning the angles over which the intensities are measured"rather than "Light blue ribbons show the 1σ scatter at each radial bin divided by the number of beams spanning the angles over which the intensities are measured."The figures themselves are unchanged from the published versions. The results and conclusions of the Letter are not affected by this error.