The Core Mass Function in the Massive Protocluster G286.21+0.17 revealed
  by ALMA
  We study the core mass function (CMF) of the massive protocluster
G286.21+0.17 with the Atacama Large Millimeter/submillimeter Array via 1.3~mm
continuum emission at a resolution of 1.0\arcsec\ (2500~au). We have mapped a
field of 5.3\arcmin$\times$5.3\arcmin\ centered on the protocluster clump. We
measure the CMF in the central region, exploring various core detection
algorithms, which give source numbers ranging from 60 to 125, depending on
parameter selection. We estimate completeness corrections due to imperfect flux
recovery and core identification via artificial core insertion experiments. For
masses $M\gtrsim1\:M_\odot$, the fiducial dendrogram-identified CMF can be fit
with a power law of the form
${\rm{d}}N/{\rm{d}}{\rm{log}}M\propto{M}^{-\alpha}$ with $\alpha
\simeq1.24\pm0.17$, slightly shallower than, but still consistent with, the
index of the Salpeter stellar initial mass function of 1.35.
Clumpfind-identified CMFs are significantly shallower with
$\alpha\simeq0.64\pm0.13$. While raw CMFs show a peak near $1\:M_\odot$,
completeness-corrected CMFs are consistent with a single power law extending
down to $\sim 0.5\:M_\odot$, with only a tentative indication of a shallowing
of the slope around $\sim1\:M_\odot$. We discuss the implications of these
results for star and star cluster formation theories.
