# The RMS Survey: 13CO observations of candidate massive YSOs in the southern hemisphere - Astrophysics

Abstract: Abridged: The Red MSX Source (RMS) survey is an ongoing multi-wavelengthobservational programme designed to return a large, well-selected sample ofmassive young stellar objects (MYSOs). Here we present 13CO observations madetowards 854 MYSOs candidates located in the 3rd and 4th quadrants. We detected13CO emission towards a total of 751 of the 854 RMS sources observed (~88%). Intotal 2185 emission components are detected above 3$\sigma$ level. Multipleemission profiles are observed towards the majority of these sources - 455sources (~60%) - with an average of ~4 molecular clouds along the line ofsight. These multiple emission features make it difficult to assign a kinematicvelocity to many of our sample. We have used archival CS (J=2-1) and maservelocities to resolved the component multiplicity towards 82 sources and havederived a criterion which is used to identify the most likely component for afurther 202 multiple component sources. Combined with the single componentdetections we have obtained unambiguous kinematic velocities towards 580sources (~80% of the detections). The 171 sources for which we have not beenable to determine the kinematic velocity will require additional line data.Using the rotation curve of Brand and Blitz (1993) and their radial velocitieswe calculate kinematic distances for all components detected.

Author: J. S. Urquhart, A. L. Busfield, M. G. Hoare, S. L. Lumsden, R. D. Oudmaijer, T. J. T. Moore, A. G. Gibb, C. R. Purcell, M. G. Bur

Source: https://arxiv.org/