Little change in the sizes of the most massive galaxies since z = 1
  Recent reports suggest that elliptical galaxies have increased their size
dramatically over the last ~8 Gyr. This result points to a major re-think of
the processes dominating the latetime evolution of galaxies. In this paper we
present the first estimates for the scale sizes of brightest cluster galaxies
(BCGs) in the redshift range 0.8 < z < 1.3 from an analysis of deep Hubble
Space Telescope imaging, comparing to a well matched local sample taken from
the Local Cluster Substructure Survey at z ~ 0.2. For a small sample of 5 high
redshift BCGs we measure half-light radii ranging from 14 - 53 kpc using de
Vaucuoleurs profile fits, with an average determined from stacking of 32.1 \pm
2.5 kpc compared to a value 43.2 \pm 1.0 kpc for the low redshift comparison
sample. This implies that the scale sizes of BCGs at z = 1 are ~ 30% smaller
than at z = 0.25. Analyses comparing either Sersic or Petrosian radii also
indicate little or no evolution between the two samples. The detection of only
modest evolution at most out to z = 1 argues against BCGs having undergone the
large increase in size reported for massive galaxies since z = 2 and in fact
the scale-size evolution of BCGs appears closer to that reported for radio
galaxies over a similar epoch. We conclude that this lack of size evolution,
particularly when coupled with recent results on the lack of BCG stellar mass
evolution, demonstrates that major merging is not an important process in the
late time evolution of these systems. The homogeneity and maturity of BCGs at z
= 1 continues to challenge galaxy evolution models.
