A Submillimeter Perspective on the GOODS Fields (SUPER GOODS). III. A
  Large Sample of ALMA Sources in the GOODS-S
  We analyze the >4-sigma sources in the most sensitive 100 arcmin^2 area (rms
<0.56 mJy) of a SCUBA-2 850 micron survey of the GOODS-S and present the 75
band 7 ALMA sources (>4.5-sigma) obtained from high-resolution interferometric
follow-up observations. The SCUBA-2---and hence ALMA---samples should be
complete to 2.25 mJy. Of the 53 SCUBA-2 sources in this complete sample, only
five have no ALMA detections, while 13% (68% confidence range 7-19%) have
multiple ALMA counterparts. Color-based high-redshift dusty galaxy selection
techniques find at most 55% of the total ALMA sample. In addition to using
literature spectroscopic and optical/NIR photometric redshifts, we estimate FIR
photometric redshifts based on an Arp 220 template. We identify seven z>4
candidates. We see the expected decline with redshift of the 4.5 micron and 24
micron to 850 micron flux ratios, confirming these as good diagnostics of z>4
candidates. We visually classify 52 ALMA sources, finding 44% (68% confidence
range 35-53%) to be apparent mergers. We calculate rest-frame 2-8 keV and 8-28
keV luminosities using the 7 Ms Chandra X-ray image. Nearly all of the ALMA
sources detected at 0.5-2 keV are consistent with a known X-ray luminosity to
850 micron flux relation for star-forming galaxies, while most of those
detected at 2-7 keV are moderate luminosity AGNs that lie just above the 2-7
keV detection threshold. The latter largely have substantial obscurations of
log N_H = 23-24 cm^-2, but two of the high-redshift candidates may even be
Compton thick.
