ALMA band 8 observations of DLA2233+131 at z=3.150
  We present our ALMA Band 8 observations of a damped Ly${\alpha}$ absorption
(DLA) system at $z$=3.150 observed in the spectrum of the quasar Q2233+131 at
$z$=3.295. The optical counterpart of this DLA has been identified and it shows
a double-peaked Ly${\alpha}$ emission line. Since one possible origin of DLAs
at high redshift is an outflowing gas from star-forming galaxies, DLA2233+131
provides a good laboratory to investigate the nature of high-$z$ DLAs.
Motivated by this, we have carried out ALMA band 8 observations to study the [C
II] line in this system. However, we do not detect any significant emission
line in the observed pass bands. Instead, we have serendipitously found three
submm continuum sources in the observed sky area. One appears to be the quasar
Q2233+131 itself while the other two sources are newly identified submm
galaxies (SMGs), called SMG1 and SMG2 in this paper. They are located at a
separation of 400.7 and 800.1 from Q2233+131, respectively. Their 646 ${\mu}$m
fluxes are 6.35 mJy and 6.43 mJy, respectively, being higher than that of
Q2233+131, 3.62 mJy. Since these two SMGs are not detected in the optical
images obtained with the Hubble Space Telescope and the Subaru Telescope, they
have a very red spectral energy distribution. It is, therefore,suggested that
they are high-redshift galaxies or very dusty galaxies at intermediate redshift
although we cannot rule out the possibility that they are optically very faint
SMG analogs at low redshift. Follow up observations will be necessary to
explore the nature of this interesting region.
