GAMA/G10-COSMOS/3D-HST: Evolution of the galaxy stellar mass function
  over 12.5Gyrs
  Using a combined and consistently analysed GAMA, G10-COSMOS, and 3D-HST
dataset we explore the evolution of the galaxy stellar-mass function over
lookback times $t_{\rm L} \in \left[0.2,12.5\right] {\rm h^{-1}_{70} Gyr}$. We
use a series of volume limited samples to fit Schechter functions in bins of
$\sim\!$constant lookback time and explore the evolution of the best-fit
parameters in both single and two-component cases. In all cases, we employ a
fitting procedure that is robust to the effects of Eddington bias and sample
variance. Surprisingly, when fitting a two-component Schechter function, we
find essentially no evidence of temporal evolution in $M_\star$, the two
$\alpha$ slope parameters, or the normalisation of the low-mass component.
Instead, our fits suggest that the various shape parameters have been
exceptionally stable over cosmic time, as has the normalisation of the low-mass
component, and that the evolution of the stellar-mass function is well
described by a simple build up of the high-mass component over time. When
fitting a single component Schechter function, there is an observed evolution
in both $M_\star$ and $\alpha$, however this is interpreted as being an
artefact. Finally, we find that the evolution of the stellar-mass function, and
the observed stellar mass density, can be well described by a simple model of
constant growth in the high-mass source density over the last $11 {\rm
h^{-1}_{70} Gyr}$.
