HXR source aspect ratio, w_b/w_a, as a function of major axis size w_a for thermal (left) and nonthermal sources (right). Also shown are power-law fits using the BCES bisector method (dashed lines), the slope α and intercept b of the obtained power law, the rank correlation coefficient R, and the number of value pairs, N. The dotted lines represent the lower threshold on w_b/w_a imposed by RHESSI’s resolution limit of 2′′. Larger sources have smaller aspect ratios, i.e., are more elongated.