Galaxy Photometric Growth Curves

Standard "growth curves" for several Hubble types (T = -5, 0, 5, 10 in blue, -2 in yellow). Input data are the three aperture magnitudes and the Hubble type (-2, S0, in this case). The growth curve for T = -2 is fit to the aperture data to yield values of A_e and B_T. Notice B_T in this case is about 0.1 mag brighter than the magnitude in the largest aperture, and represents an extrapolation of the galaxy light "to infinity". Hence B_T is a total magnitude.