Hot Molecular Core Candidates in the Galactic Center 50 km/s Molecular
  Cloud
  We present the results based on the 2.5 arcsec-resolution observations using
Atacama Large Millimeter/submillimeter Array (ALMA) of the Galactic Center
Molecular Cloud G-0.02-0.07, or the 50 km/s Molecular Cloud (50MC), in the SO
(N_J=2_2-1_1) line and 86-GHz continuum emission, the combination of which is
considered to trace "hot molecular core candidates" (HMCCs) appearing in the
early stage of massive star formation. In the 86-GHz continuum image, we
identified nine dust cores in the central part of the 50MC, in which four
famous compact HII regions are located. No new ultra-compact HII regions were
found. We also identified 28 HMCCs in the 50MC with the SO line. The overall SO
distribution had no clear positional correlation with the identified HII
regions. The HMCCs in the 50MC showed a variety of association and
non-association with dust and Class-I CH3OH maser emissions. The variety
suggests that they are not in a single evolutionary stage or environment.
Nevertheless, the masses of the identified HMCCs were found to be well
approximated by a single power law of their radii, M_LTE/(M_sun)=5.44 x 10^5
(r/(pc))^2.17 at T_ex = 50-100 K. The derived HMCC masses were larger than
those of the molecular cores with the same radii in the 50MC and also than
those of the molecular clumps in the Galactic disk. Additional observations are
needed to confirm the nature of these HMCCs in the 50MC.
