GOODS-ALMA: 1.1 mm galaxy survey - I. Source catalogue and optically
  dark galaxies
  We present a 69 arcmin$^2$ ALMA survey at 1.1mm, GOODS-ALMA, matching the
deepest HST-WFC3 H-band part of the GOODS-South field. We taper the 0"24
original image with a homogeneous and circular synthesized beam of 0"60 to
reduce the number of independent beams - thus reducing the number of purely
statistical spurious detections - and optimize the sensitivity to point
sources. We extract a catalogue of galaxies purely selected by ALMA and
identify sources with and without HST counterparts down to a 5$\sigma$ limiting
depth of H=28.2 AB (HST/WFC3 F160W). ALMA detects 20 sources brighter than 0.7
mJy in the 0"60 tapered mosaic (rms sensitivity =0.18 mJy/beam) with a purity
greater than 80%. Among these detections, we identify three sources with no HST
nor Spitzer-IRAC counterpart, consistent with the expected number of spurious
galaxies from the analysis of the inverted image; their definitive status will
require additional investigation. An additional three sources with HST
counterparts are detected either at high significance in the higher resolution
map, or with different detection-algorithm parameters ensuring a purity greater
than 80%. Hence we identify in total 20 robust detections. Our wide contiguous
survey allows us to push further in redshift the blind detection of massive
galaxies with ALMA with a median redshift of $z$=2.92 and a median stellar mass
of M$_{\star}$ = 1.1 $\times 10^{11}$M$_\odot$. Our sample includes 20%
HST-dark galaxies (4 out of 20), all detected in the mid-infrared with IRAC.
The near-infrared based photometric redshifts of two of them $z\sim$4.3 and
4.8) suggest that these sources have redshifts $z$>4. At least 40% of the ALMA
sources host an X-ray AGN, compared to 14% for other galaxies of similar mass
and redshift. The wide area of our ALMA survey provides lower values at the
bright end of number counts than single-dish telescopes
