Paper detail

The Tolman Surface Brightness Test for the Reality of the Expansion. V. Provenance of the Test and a New Representation of the Data for Three Remote HST Galaxy Clusters

A new reduction is made of the HST photometric data for E galaxies in three remote clusters at redshifts near z=0.85 in search for the Tolman surface brightness (SB) signal for the reality of the expansion. Because of the strong variation of SB of such galaxies with intrinsic size, and because the Tolman test is about surface brightness, we must account for the variation. In an earlier version of the test, Lubin & Sandage calibrated the variation out. In contrast, the test is made here using fixed radius bins for both the local and remote samples. Homologous positions in the galaxy image at which to compare the surface brightness values are defined by radii at five Petrosian eta values ranging from 1.0 to 2.0. Sersic luminosity profiles are used to generate two diagnostic diagrams that define the mean SB distribution across the galaxy image. A Sersic exponent, defined by the r^n family of Sersic profiles, of n=0.46 fits both the local and remote samples. Diagrams of the dimming of the <SB> with redshift over the range of Petrosian eta radii shows a highly significance Tolman signal but degraded by luminosity evolution in the look-back time. The expansion is real and a luminosity evolution exists at the mean redshift of the HST clusters of 0.8 mag in R_cape and 0.4 mag in the I_cape photometric rest-frame bands, consistent with the evolution models of Bruzual and Charlot.