GOODS-ALMA 2.0: Source catalog, number counts, and prevailing compact
  sizes in 1.1 mm galaxies
  Submillimeter/millimeter observations of dusty star-forming galaxies with the
Atacama Large Millimeter/submillimeter Array (ALMA) have shown that dust
continuum emission generally occurs in compact regions smaller than the stellar
distribution. However, it remains to be understood how systematic these
findings are. Studies often lack homogeneity in the sample selection, target
discontinuous areas with inhomogeneous sensitivities, and suffer from modest
$uv$ coverage coming from single array configurations. GOODS-ALMA is a 1.1mm
galaxy survey over a continuous area of 72.42arcmin$^2$ at a homogeneous
sensitivity. In this version 2.0, we present a new low resolution dataset and
its combination with the previous high resolution dataset from the survey,
improving the $uv$ coverage and sensitivity reaching an average of $\sigma =
68.4\mu$Jy beam$^{-1}$. A total of 88 galaxies are detected in a blind search
(compared to 35 in the high resolution dataset alone), 50% at $S/N_{peak} \geq
5$ and 50% at $3.5 \leq S/N_{peak} \leq 5$ aided by priors. Among them, 13 out
of the 88 are optically dark or faint sources ($H$- or $K$-band dropouts). The
sample dust continuum sizes at 1.1mm are generally compact, with a median
effective radius of $R_{e} = 0"10 \pm 0"05$ (a physical size of $R_{e} = 0.73
\pm 0.29$kpc at the redshift of each source). Dust continuum sizes evolve with
redshift and stellar mass resembling the trends of the stellar sizes measured
at optical wavelengths, albeit a lower normalization compared to those of
late-type galaxies. We conclude that for sources with flux densities $S_{1.1mm}
> 1$mJy, compact dust continuum emission at 1.1mm prevails, and sizes as
extended as typical star-forming stellar disks are rare. The $S_{1.1mm} < 1$mJy
sources appear slightly more extended at 1.1mm, although they are still
generally compact below the sizes of typical star-forming stellar disks.
