ALMA Observations of the IRDC Clump G34.43+00.24 MM3: Hot Core and
  Molecular Outflows
  We have observed a cluster forming clump (MM3) associated with the infrared
dark cloud G34.43+00.24 in the 1.3 mm continuum and the CH3OH, CS, 13CS, SiO,
CH3CH2CN, and HCOOCH3 lines with the Atacama Large Millimeter/submillimeter
Array and in K-band with the Keck telescope. We have found a young outflow
toward the center of this clump in the SiO, CS, and CH3OH lines. This outflow
is likely driven by a protostar embedded in a hot core, which is traced by the
CH3CH2CN, HCOOCH3, 13CS, and high excitation CH3OH lines. The size of the hot
core is about 800 x 300 AU in spite of its low mass (<1.1 M_sun), suggesting a
high accretion rate or the presence of multiple star system harboring a few hot
corinos. The outflow is highly collimated, and the dynamical timescale is
estimated to be less than 740 yr. In addition, we have also detected extended
emission of SiO, CS, and CH3OH, which is not associated with the hot core and
the outflow. This emission may be related to past star formation activity in
the clump. Although G34.43+00.24 MM3 is surrounded by a dark feature in
infrared, it has already experienced active formation of low-mass stars in an
early stage of clump evolution.
