A low-velocity bipolar outflow from a deeply embedded object in Taurus
  revealed by the Atacama Compact Array
  The first hydrostatic core, the first quasi-hydrostatic object formed during
the star formation process, is still the observational missing link between the
prestellar and protostellar phases, mainly due to its short lifetime. Although
we have not established a clear method to identify this rare object, recent
theoretical studies predict that the first core has millimeter continuum
emission and low-velocity outflow with a wide opening angle. An extensive
continuum/outflow survey toward a large number of $"$starless$"$ cores in
nearby star-forming regions works as a pathfinder. We observed 32 prestellar
cores in Taurus with an average density of $\gtrsim$10$^5$ cm$^{-3}$ in 1.3 mm
continuum and molecular lines using the Atacama Large Millimeter/submillimeter
Array$-$Atacama Compact Array (ALMA$-$ACA) stand-alone mode. Among the targets,
MC35-mm centered at one of the densest $"$starless$"$ cores in Taurus has
blueshifted/redshifted wings in the $^{12}$CO (2-1) line, indicating that there
is deeply embedded object driving molecular outflow. The observed velocities
and sizes of the possible outflow lobes are 2-4 km s$^{-1}$, and $\sim$2
$\times$10$^3$ au, respectively, and the dynamical time is calculated to be
$\sim$10$^3$ yr. In addition to this, the core is one of the strongest
N$_2$D$^{+}$ (3-2) emitters in our sample. All of the observed signatures do
not conflict with any of the theoretical predictions about the first
hydrostatic core so far, and thus MC35-mm is unique as the only first-core
candidate in the Taurus molecular cloud.
