CO Outflow Candidates Toward the W3/4/5 Complex I: The Sample and its
  Spatial Distribution
  Using the Purple Mountain Observatory Delingha 13.7 m telescope, we conducted
a large-scale $^{12}$CO $\left(J=1 \rightarrow 0\right)$ outflow survey (over
$\sim$ 110 deg$^2$) toward the W3/4/5 complex and its surroundings. In total,
459 outflow candidates were identified. Approximately 62\% (284) were located
in the Perseus arm, including W3/4/5 complex and its surroundings, while $\sim$
35\% (162) were located in the Local arm, $\sim$ 1\% (5) in the Outer arm, and
$\sim$ 2\% (8) in two interarm regions. This result indicated that star
formation was concentrated in the Galactic spiral arms. The detailed spatial
distribution of the outflow candidates showed that the Perseus arm presented
the most active star formation among the study regions. The W3/4/5 complex is a
great region to research massive star formation in a triggered environment. A
key region, which has been well-studied by other researches, is in the eastern
high-density W3 complex that neighbors the W4 complex. Two shell-like
structures in the Local arm contain candidates that can be used to study the
impact on star formation imposed by massive or intermediate-mass stars in
relatively isolated systems. The majority of outflow candidates in the two
interarm regions and the Outer arm are located in filamentary structures.
