  We present cosmological constraints from the Dark Energy Survey (DES) using a
combined analysis of angular clustering of red galaxies and their
cross-correlation with weak gravitational lensing of background galaxies. We
use a 139 square degree contiguous patch of DES data from the Science
Verification (SV) period of observations. Using large scale measurements, we
constrain the matter density of the Universe as Omega_m = 0.31 +/- 0.09 and the
clustering amplitude of the matter power spectrum as sigma_8 = 0.74 +/- 0.13
after marginalizing over seven nuisance parameters and three additional
cosmological parameters. This translates into S_8 = sigma_8(Omega_m/0.3)^{0.16}
= 0.74 +/- 0.12 for our fiducial lens redshift bin at 0.35 <z< 0.5, while S_8 =
0.78 +/- 0.09 using two bins over the range 0.2 <z< 0.5. We study the
robustness of the results under changes in the data vectors, modelling and
systematics treatment, including photometric redshift and shear calibration
uncertainties, and find consistency in the derived cosmological parameters. We
show that our results are consistent with previous cosmological analyses from
DES and other data sets and conclude with a joint analysis of DES angular
clustering and galaxy-galaxy lensing with Planck CMB data, Baryon Accoustic
Oscillations and Supernova type Ia measurements.
