Sulfur-bearing molecules in Orion KL
  We present an observational study of the sulfur (S)-bearing species towards
Orion KL at 1.3 mm by combining ALMA and IRAM-30\,m single-dish data. At a
linear resolution of $\sim$800 au and a velocity resolution of 1 $\mathrm{km\,
s^{-1}\, }$, we have identified 79 molecular lines from 6 S-bearing species. In
these S-bearing species, we found a clear dichotomy between carbon-sulfur
compounds and carbon-free S-bearing species in various characteristics, e.g.,
line profiles, spatial morphology, and molecular abundances with respect to
$\rm H_2$. Lines from the carbon-sulfur compounds (i.e., OCS, $^{13}$CS,
H$_2$CS) exhibit spatial distributions concentrated around the continuum peaks
and extended to the south ridge. The full width at half maximum (FWHM)
linewidth of these molecular lines is in the range of 2 $\sim$ 11 $\mathrm{km\,
s^{-1}\, }$. The molecular abundances of OCS and H$_2$CS decrease slightly from
the cold ($\sim$68 K) to the hot ($\sim$176 K) regions. In contrast, lines from
the carbon-free S-bearing species (i.e., SO$_2$, $^{34}$SO, H$_2$S) are
spatially more extended to the northeast of mm4, exhibiting broader FWHM
linewidths (15 $\sim$ 26 $\mathrm{km\, s^{-1}\, }$). The molecular abundances
of carbon-free S-bearing species increase by over an order of magnitude as the
temperature increase from 50 K to 100 K. In particular,
$\mathrm{^{34}SO/^{34}SO_2}$ and $\mathrm{OCS/SO_2}$ are enhanced from the
warmer regions ($>$100 K) to the colder regions ($\sim$50 K). Such enhancements
are consistent with the transformation of SO$_2$ at warmer regions and the
influence of shocks.
