2003ApJ...584..357K

We have searched for CO molecular outflows associated with the cloud A and B2 of the ρ Ophiuchi star-forming region. On the basis of single -dish ¹²CO (J=3-2) and interferometric ¹²CO (J=1-0) observations, we have identified three molecular outflows in the ρ Oph A cloud and one in the ρ 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_COof newly detected outflows are roughly comparable to those of Class I objects observed by Bontemps et al. ((ref???)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 ρ Oph A region and the northeastern condensation in the ρ Oph B2 region, suggesting that they are considered to be pre-protostellar cores.