A study of dense cloud cores and star formation in Lupus:: C18O J=1-0 observations with NANTEN

We have made an extensive study of dense cloud cores and star formation in the Lupus dark-cloud complex. Millimeter-wave observations in the (CO)-O-18 (J = 1-0) emission at 2.6 mm wavelength mere made with the "NANTEN,," a 4-m mm-wave telescope of Nagoya University at Las Campanas Observatory. Thirty-six dense cores were identified and mapped in the (CO)-O-18 emission at 2' grid spacing with a 2.'7 beam. The typical mass, radius, Ha column density, and line width of the (CO)-O-18 COTES are 9.7M., 0.17 pc, 4.1 x 10(21) cm(-2), 0.90 km s(-1), respectively. The mass spectrum of the (CO)-O-18 cores was fitted by a single power-law index of gamma = -1.7 +/- 0.6 for M-core greater than or equal to 3 M.. The physical parameters of the dense (CO)-O-18 cores were derived and compared with those in Taurus, Ophiuchus North, and L 1333. The average characteristics of the (CO)-O-18 cores in Lupus are similar to those in Ophiuchus North and L 1333, although those in Taurus are found to be different, especially in the line width, virial ratio, and mass spectrum index among the four regions. By comparing the physical properties of the (CO)-O-18 cores with the distribution of YSOs and (HCO+)-C-13 condensations in Lupus, we have confirmed a trend suggested in previous studies, that star formation preferentially occurs in cores having a small virial ratio: M-vir/M-core and a large H-2 column density.