Physical Characterization of Serendipitously Uncovered Millimeter-wave
  Line-emitting Galaxies at z~2.5 behind the Local Luminous Infrared Galaxy
  VV114
  We present a detailed investigation of millimeter-wave line emitters ALMA
J010748.3-173028 (ALMA-J0107a) and ALMA J010747.0-173010 (ALMA-J0107b), which
were serendipitously uncovered in the background of the nearby galaxy VV114
with spectral scan observations at $\lambda$ = 2 - 3 mm. Via Atacama Large
Millimeter/submillimeter Array (ALMA) detection of CO(4-3), CO(3-2), and
[CI](1-0) lines for both sources, their spectroscopic redshifts are
unambiguously determined to be $z= 2.4666\pm0.0002$ and $z=2.3100\pm0.0002$,
respectively. We obtain the apparent molecular gas masses $M_{\rm gas}$ of
these two line emitters from [CI] line fluxes as $(11.2 \pm 3.1) \times 10^{10}
M_\odot$ and $(4.2 \pm 1.2) \times 10^{10} M_\odot$, respectively. The observed
CO(4-3) velocity field of ALMA-J0107a exhibits a clear velocity gradient across
the CO disk, and we find that ALMA-J0107a is characterized by an inclined
rotating disk with a significant turbulence, that is, a deprojected maximum
rotation velocity to velocity dispersion ratio $v_{\rm max}/\sigma_{v}$ of $1.3
\pm 0.3$. We find that the dynamical mass of ALMA-J0107a within the CO-emitting
disk computed from the derived kinetic parameters, $(1.1 \pm 0.2) \times
10^{10}\ M_\odot$, is an order of magnitude smaller than the molecular gas mass
derived from dust continuum emission, $(3.2\pm1.6)\times10^{11}\ M_{\odot}$. We
suggest this source is magnified by a gravitational lens with a magnification
of $\mu \gtrsim10$, which is consistent with the measured offset from the
empirical correlation between CO-line luminosity and width.
