In the outermost regions, photon noise and statistical uncertainty in the sky subtraction begin to dominate causing the output profile to artificially level off at large radii. Crosses show the bulge component of N42 after model subtraction. After subtraction, this leaves the inner bulge component, with , and extending out to , as evident from Fig. 1 . For this reason this galaxy was not included in any subsequent analysis. We will turn back on this point and its impact on the L - N relationship in Sect.
North is up and East to the left.
Orientation and scale are the same as in the upper panel.