Astron. Astrophys. Suppl. Ser. 140, 177-190

Outflow sources in the Vela region

J.G.A. Wouterloot¹ - J. Brand²

Send offprint request: J.G.A. Wouterloot

1 - Radioastronomisches Institut, Universität Bonn, Auf dem Hügel 71, D-53121 Bonn, Germany
e-mail: wouterloot@astro.uni-bonn.de
2 - Istituto di Radioastronomia, CNR, Via Gobetti 101, I-40129 Bologna, Italy
e-mail: brand@terra.bo.cnr.it

Received July 9; accepted August 25, 1999

Abstract:

We have observed ¹²CO(1-0), ¹³CO(1-0), C¹⁸O(1-0), and CS(2-1) towards nine sources in the Vela region for which the ¹²CO(1-0) spectra by Wouterloot & Brand ([1989]) suggested the presence of strong line wings (towards two of those sources only CS or ¹²CO and ¹³CO were observed). The sources are located in or behind the Vela Molecular Ridge at distances between about 0.6 and 6.7 kpc. In all transitions we made small maps, typically several arcminutes in size.

Towards five sources the ¹²CO emission is confused by unrelated components at other velocities (not visible in CS and C¹⁸O) which we subtracted from the line profiles before analysing the wing emission. The presence of outflow emission was studied by also subtracting the contribution of a central Gaussian line component. We conclude that of the eight sources observed in CO, seven show outflows, one does not. For one of the sources only the blue wing could be studied due to the confusing presence of other strong line components. For the outflow sources we derive the physical parameters. Wing emission has a relative outflow velocity up to about 16 km$\,$s^-1, but the average (weighted with line intensity) is about 4 km$\,$s^-1. Masses of the outflows range from 1 to 150 $M_\odot$.

CS and C¹⁸O were detected towards all eight (resp. seven) sources observed in these molecules. Five sources show single clumps in both transitions, two sources show several clumps in one of the transitions (the other was not mapped completely) and one source shows only weak emission (probably due to its distance). Clump masses and radii range from several 10 $M_\odot$ to about 1000 $M_\odot$ and 0.2 pc to 2 pc. Five of the sources show a velocity gradient in CS and C¹⁸O indicative of rotation.

Key words: ISM: clouds -- molecules -- radio lines: ISM