The clustering of H-alpha emitters at z=2.23 from HiZELS
  (abridged) We present a clustering analysis of 370 high-confidence H-alpha
emitters (HAEs) at z=2.23. The HAEs are detected in the Hi-Z Emission Line
Survey (HiZELS), a large-area blank field 2.121um narrowband survey using the
United Kingdom Infrared Telescope (UKIRT) Wide Field Camera (WFCAM). Averaging
the two-point correlation function of HAEs in two ~1 degree scale fields
(United Kingdom Infrared Deep Sky Survey/Ultra Deep Survey [UDS] and
Cosmological Evolution Survey [COSMOS] fields) we find a clustering amplitude
equivalent to a correlation length of r_0=3.7+/-0.3 Mpc/h for galaxies with
star formation rates of >7 M_sun/yr. The data are well-fitted by the expected
correlation function of Cold Dark Matter, scaled by a bias factor:
omega_HAE=b^2 omega_DM where b=2.4^{+0.1}_{-0.2}. The corresponding
'characteristic' mass for the halos hosting HAEs is
log(M_h/[M_sun/h])=11.7+/-0.1. Comparing to the latest semi-analytic GALFORM
predictions for the evolution of HAEs in a LCDM cosmology, we find broad
agreement with the observations, with GALFORM predicting a HAE correlation
length of ~4 Mpc/h. Motivated by this agreement, we exploit the simulations to
construct a parametric model of the halo occupation distribution (HOD) of HAEs,
and use this to fit the observed clustering. Our best-fitting HOD can
adequately reproduce the observed angular clustering of HAEs, yielding an
effective halo mass and bias in agreement with that derived from the scaled
omega_DM fit, but with the relatively small sample size the current data
provide a poor constraint on the HOD. Our results support the broad picture
that 'typical' (~L*) star-forming galaxies have been hosted by dark matter
haloes with M_h<10^12 M_sun/h since z~2, but with a broad occupation
distribution and clustering that is likely to be a strong function of
luminosity.
