Surface number density profiles of RGB stars in the central regions of the three galaxies (shown in red), the dashed lines are the best-fit models, the dash-dotted lines show the different components, two sech² functions, and a constant for background contamination. The light blue dashed line is the (background-subtracted) surface brightness in the Spitzer 3.6 μm filter, the solid blue line shows the Spitzer data averaged to the same bin size as the star count data, and the horizontal gray line plots the estimated noise level of the background of the Spitzer data.