A pilot survey for transients and variables with the Australian Square
  Kilometre Array Pathfinder
  We present a pilot search for variable and transient sources at 1.4 GHz with
the Australian Square Kilometre Array Pathfinder (ASKAP). The search was
performed in a 30 deg$^{2}$ area centred on the NGC 7232 galaxy group over 8
epochs and observed with a near-daily cadence. The search yielded nine
potential variable sources, rejecting the null hypothesis that the flux
densities of these sources do not change with 99.9% confidence. These nine
sources displayed flux density variations with modulation indices m $\geq 0.1$
above our flux density limit of 1.5 mJy. They are identified to be compact
AGN/quasars or galaxies hosting an AGN, whose variability is consistent with
refractive interstellar scintillation. We also detect a highly variable source
with modulation index m $ > 0.5$ over a time interval of a decade between the
Sydney University Molonglo Sky Survey (SUMSS) and our latest ASKAP
observations. We find the source to be consistent with the properties of
long-term variability of a quasar. No transients were detected on timescales of
days and we place an upper limit $\rho < 0.01$ deg$^{2}$ with 95% confidence
for non-detections on near-daily timescales. The future VAST-Wide survey with
36-ASKAP dishes will probe the transient phase space with a similar cadence to
our pilot survey, but better sensitivity, and will detect and monitor rarer
brighter events.
