Credit: Astrophysics Laboratory, Nagoya University
Figure 3. Three-dimensional fitting of a flat plane expressed by an equation of Ng = a Np + b Nx, where a and b are constants. The data points are colored by the code in the figure according to Ng and are shown by filled and open symbols for those above and below the plane. The blue, green, yellow, and red represent Ng is less than 1.2 counts arcmin−2, 1.2–1.7 counts arcmin−2, 1.7–2.2 counts arcmin−2, and greater than 2.2 counts arcmin−2, respectively. The blue, green, orange, red, and purple dashed lines on the best-fit plane indicate 1.0, 1.5, 2.0, 2.5, and 3.0 counts arcmin−2, respectively.