Detection of the kinematic Sunyaev-Zel'dovich effect with DES Year 1 and
  SPT
  We detect the kinematic Sunyaev-Zel'dovich (kSZ) effect with a statistical
significance of $4.2 \sigma$ by combining a cluster catalogue derived from the
first year data of the Dark Energy Survey (DES) with CMB temperature maps from
the South Pole Telescope Sunyaev-Zel'dovich (SPT-SZ) Survey. This measurement
is performed with a differential statistic that isolates the pairwise kSZ
signal, providing the first detection of the large-scale, pairwise motion of
clusters using redshifts derived from photometric data. By fitting the pairwise
kSZ signal to a theoretical template we measure the average central optical
depth of the cluster sample, $\bar{\tau}_e = (3.75 \pm 0.89)\cdot 10^{-3}$. We
compare the extracted signal to realistic simulations and find good agreement
with respect to the signal-to-noise, the constraint on $\bar{\tau}_e$, and the
corresponding gas fraction. High-precision measurements of the pairwise kSZ
signal with future data will be able to place constraints on the baryonic
physics of galaxy clusters, and could be used to probe gravity on scales $
\gtrsim 100$ Mpc.
