We have observed two rotational transitions of both CS and C^17^O, and the 1.2mm continuum emission towards a sample of 130 high-mass protostellar candidates with DE=-30{deg}, we have selected from the IRAS Point Source Catalogue 429 sources which potentially are compact molecular clouds on the basis of their IR colours. The sample has then been divided into two groups according to the colour indices [25-12] and [60-12]: the 298 sources with [25-12]>=0.57 and [60-12]>=1.30 have been called High sources, the remaining 131 have been called Low sources. In this paper, we check the association with dense gas and dust in 130 Low sources. We have obtained a detection rate of ~85% in CS, demonstrating a tight association of the sources with dense molecular clumps.

Cone search capability for table J/A+A/432/921/tablea1 (Observed sources and detection summary)