We present the results of C ^ { 18 } O ( J =1–0 ) mapping observations of a 20 ^ { \prime } \times 18 ^ { \prime } area in the Lynds 1204 molecular cloud associated with the Sharpless 2-140 ( S140 ) H ii region .
The C ^ { 18 } O cube ( \alpha - \delta - v _ { LSR } ) data shows that there are three clumps with sizes of \sim 1 pc in the region .
Two of them have peculiar red shifted velocity components at their edges , which can be interpreted as the results of the interaction between the cloud and the Cepheus Bubble .
From the C ^ { 18 } O cube data , the clumpfind identified 123 C ^ { 18 } O cores , which have mean radius , velocity width in FWHM , and LTE mass of 0.36 \pm 0.07 pc , 0.37 \pm 0.09 km s ^ { -1 } , and 41 \pm 29 M _ { \odot } , respectively .
All the cores in S140 are most likely to be gravitationally bound by considering the uncertainty in the C ^ { 18 } O abundance .
We derived a C ^ { 18 } O core mass function ( CMF ) , which shows a power-law-like behavior above a turnover at 30 M _ { \odot } .
The best-fit power-law index of -2.1 \pm 0.2 is quite consistent with those of the IMF and the C ^ { 18 } O CMF in the OMC-1 region by Ikeda & Kitamura ( 12 ) . Kramer et al .
( 16 ) estimated the power-law index of - 1.65 in S140 from the C ^ { 18 } O ( J =2–1 ) data , which is inconsistent with this study .
However , the C ^ { 18 } O ( J =2–1 ) data are spatially limited to the central part of the cloud and are likely to be biased toward high-mass cores , leading to the flatter CMF .
Consequently , this study and our previous one strongly support that the power-law form of the IMF has been already determined at the density of \lesssim 10 ^ { 3 \mbox { \scriptsize - - } 4 } cm ^ { -3 } , traced by the C ^ { 18 } O ( J =1–0 ) line .