Three isotopologues CO survey of Molecular Clouds in the CMa OB1 complex
  Using the Purple Mountain Observatory 13.7-m millimeter telescope at Delingha
in China, we have conducted a large-scale simultaneous survey of $^{12}$CO,
$^{13}$CO, and \xxco ($J$ = 1--0) toward the CMa OB1 complex with a sky
coverage of 16.5 deg$^{\rm 2}$ ($221^{\circ}.5\leq l\leq227^{\circ}$,
$-2^{\circ}.5\leq b\leq0^{\circ}.5$). Emission from the CMa OB1 complex is
found in the range 7 km s$^{-1}\ \leq$ V$_\mathrm{LSR}\ \leq$ 25 km s$^{-1}$.
The large-scale structure, physical properties and chemical abundances of the
molecular clouds are presented. A total of 83 C$^{18}$O molecular clumps are
identified with GaussClumps algorithm within the mapped region. We find that
94% of these C$^{18}$O molecular clumps are gravitationally bound. The
relationship between their size and mass indicates that none of the C$^{18}$O
clump has the potential to form high-mass stars. Using semi-automatic IDL
algorithm, we newly discover 85 CO outflow candidates in the mapped area,
including 23 bipolar outflows candidates. Additionally, a comparative study
reveals evidence for significant variety of physical properties, evolutionary
stages, and levels of star formation activity in different sub-regions of the
CMa OB1 complex.
