Search for Molecular Clouds toward Intermediate-to-High Latitude IRAS Sources in the Southern Sky

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We have conducted a search for molecular clouds toward southern IRAS point sources at intermediate-to-high galactic latitude (|b| ≥ 10° in 12CO (J = 1−0) emission with the NANTEN telescope. The main purpose of the survey was to find a new sample of star-forming clouds unknown to date. Of the 29 targets, we detected CO emission toward 5 IRAS sources, i.e., 04591–0856, 05044–0325, 05050–0614, 06345–3023, and 13543–3941. Among 5 detections, the molecular cloud associated with 06345–3023 (G 239.2–16.3) was detected for the first time. If we assume the distance as being 1.5 kpc, this\ source is ∼ 430 pc away from the galactic plane. Three sources 04591–0856 (G 208.3–28.4), 05044–0325 (G 203.5–24.7), and 05050–0614 (G 206.4–25.9) are located west to the Orion molecular clouds, and 13543-3941 (G 316.4+21.2) is located in the cometary globule CG 12. Four of the 5 clouds show a cometary shape with a “head-tail” distribution, and three of them have the IRAS source located at the edge opposite to the tail. We find that all of the CO clouds are associated with the optical nebulosities, which are likely to be reflection nebulae. A comparison of the present CO clouds with those in Ophiuchus, Taurus, Chamaeleon, and L 1333 indicates that star-forming clouds tend to have a high column density, as well as a smaller ratio of the virial mass to the LTE mass.