A new methodology to test galaxy formation models using the dependence
  of clustering on stellar mass
  We present predictions for the two-point correlation function of galaxy
clustering as a function of stellar mass, computed using two new versions of
the GALFORM semi-analytic galaxy formation model. These models make use of a
high resolution, large volume N-body simulation, set in the WMAP7 cosmology.
One model uses a universal stellar initial mass function (IMF), while the other
assumes different IMFs for quiescent star formation and bursts. Particular
consideration is given to how the assumptions required to estimate the stellar
masses of observed galaxies (such as the choice of IMF, stellar population
synthesis model and dust extinction) influence the perceived dependence of
galaxy clustering on stellar mass. Broad-band spectral energy distribution
fitting is carried out to estimate stellar masses for the model galaxies in the
same manner as in observational studies. We show clear differences between the
clustering signals computed using the true and estimated model stellar masses.
As such, we highlight the importance of applying our methodology to compare
theoretical models to observations. We introduce an alternative scheme for the
calculation of the merger timescales for satellite galaxies in GALFORM, which
takes into account the dark matter subhalo information from the simulation.
This reduces the amplitude of small-scale clustering. The new merger scheme
offers improved or similar agreement with observational clustering
measurements, over the redshift range 0 < z < 0.7. We find reasonable agreement
with clustering measurements from GAMA, but find larger discrepancies for some
stellar mass ranges and separation scales with respect to measurements from
SDSS and VIPERS, depending on the GALFORM model used.
