Molecular outflow search in the ρ Ophiuchi A and B2 regions

We have searched for CO molecular outflows associated with the cloud A and B2 of the rho Ophiuchi star-forming region. On the basis of single-dish (CO)-C-12 (J=3-2) and interferometric (CO)-C-12 (J=1-0) observations, we have identified three molecular outflows in the rho Oph A cloud and one in the rho Oph B2 cloud. Out of the four outflows observed in these regions, one is the known outflow driven by the Class 0 source, VLA 1623, and the other three are newly discovered ones. The inclination and opacity corrected momentum flux F-CO of newly detected outflows are roughly comparable to those of Class I objects observed by Bontemps et al. (1996). All the newly discovered outflows are likely to be driven by Class II sources or near-infrared sources, and none of them is associated with the cold submillimeter-millimeter sources without infrared counter parts. These results indicate that protostars associated with outflows whose mass and momentum flux exceed our detection limit are not formed yet in the high-density ridge of the rho Oph A region and the northeastern condensation in the rho Oph B2 region, suggesting that they are considered to be pre-protostellar cores.