Carbon Monoxide Observations Toward Star Forming Regions in the Outer
  Scutum-Centaurus Spiral Arm
  The Outer Scutum-Centaurus arm (OSC) is the most distant molecular spiral arm
known in the Milky Way. The OSC may be the very distant end of the well-known
Scutum-Centaurus arm, which stretches from the end of the Galactic bar to the
outer Galaxy. At this distance the OSC is seen in the first Galactic quadrant.
The population of star formation tracers in the OSC remains largely
uncharacterized. Extragalactic studies show a strong correlation between
molecular gas and star formation, and carbon monoxide (CO) emission was
recently discovered in the OSC. Here we use the Arizona Radio Observatory (ARO)
12-m telescope to observe the $^{12}$CO J = 1-0 and $^{13}$CO J = 1-0
transitions toward 78 HII region candidates chosen from the WISE Catalog of
Galactic HII Regions. These targets are spatially coincident with the Galactic
longitude-latitude ($\ell, b$) OSC locus as defined by HI emission. We detect
CO emission in $\sim 80$% of our targets. In total, we detect 117 $^{12}$CO and
40 $^{13}$CO emission lines. About 2/3 of our targets have at least one
emission line originating beyond the Solar orbit. Most of the detections beyond
the Solar orbit are associated with the Outer Arm, but there are 17 $^{12}$CO
emission lines and 8 $^{13}$CO emission lines with LSR velocities that are
consistent with the velocities of the OSC. There is no apparent difference
between the physical properties (e.g., molecular column density) of these OSC
molecular clouds and non--OSC molecular clouds within our sample.
