In molecular clouds there are regions of energetic mass outflow, that are restricted to a small area of a cloud, usually surrounding an embedded young stellar object (YSO; see e.g. Lada [1985]; Bachiller [1996]). The typical signature of these outflows are broad (up to $\approx$ 20 km s^-1 for "standard high-velocity'' flows; up to 150 km s^-1 for the weak, "extremely high-velocity'' flows), low-level emission superimposed on a narrow emission line. The broad component is often distributed in a bipolar fashion. As these flows are much more often associated with embedded IR sources than with optically visible YSO's, it is thought that this phenomenon may be one of the earliest (first 10⁵ years) identifiable stages of stellar evolution (of both massive and low-mass stars). The gas is not gravitationally bound, because for typical flow velocities of 10 km s^-1 and sizes of a few tenths of a parsec, 10⁴ $M_\odot$ is required to bind the gas; this is much more than the typical mass of a molecular cloud clump in which the flows occur. Other phenomena that are associated with molecular outflows are HH-objects, H₂O maser emission, and shock-excited H₂ emission.

The flows are relatively cold (10-20 K), low-to-moderate density (300-3000 cm^-3) streams of molecular gas with a mass in the range 0.01-200 $M_\odot$ , that are easily studied in the isotopomers of the CO molecule. From such observations it is found that clumping of material in the flow is common. Observations of molecules that trace higher-density regions (10³-10⁵ cm^-3) of a cloud (e.g. CS, HCN, SO) reveal (Tafalla et al. [1997]) that higher densities do occur in the region of the flow, but that they are much more clumped than the CO. It is assumed that the molecular outflows are driven and directed by stellar jets (DeYoung [1986]), rather than by winds originating from the star/disk system (Shu et al. [1991]).

**Table 1:** Observed sources
Source	$\alpha$ (1950)	$\delta$ (1950)	$\it {l}$	$\it {b}$	$V_{\rm {lsr}}$	Dist.¹	$L_{\rm {fir}}$	Ass.	Remarks
	h m s	$^\circ$ $^\prime$ $^{\prime \prime }$	$^\circ$	$^\circ$	km s^-1	kpc	$L_\odot$
WB89 1086	07 59 51.4	-28 14 28	245.93	1.16	63.7	6.67	5400	Bran96
WB89 1099	08 07 40.2	-35 56 07	253.92	-1.61	5.8	0.75	46	CG30-IRS4, HH120,
								Bran111, DC253.3-1.6
WB89 1135	08 21 17.9	-41 46 10	259.61	-2.70	54.6	6.42	14000
WB89 1173	08 39 23.4	-40 41 18	260.78	0.68	7.4	1.35	480
WB89 1181	08 44 49.4	-43 43 28	263.78	-0.43	4.1	0.98	1630
WB89 1187	08 47 01.3	-43 21 15	263.74	0.12	12.1	2.24	7100
WB89 1189	08 47 39.4	-43 06 01	263.82	0.37	2.5	0.59	310
WB89 1262	09 14 57.9	-47 43 50	270.26	0.84	9.5	3.40	38900	Bran246, RCW41,	only CS
								G270.26+0.83
WB89 1275	09 22 45.9	-51 46 36	274.01	-1.15	36.9	6.38	936000	Bran263, RCW42	only ¹²CO,
									¹³CO
¹ Kinematic distance, except for WB89 1086 and 1262 (photometric distance from Brand & Blitz [1993]).

The kinetic energies that are associated with the flows are typically 10⁴⁵ erg; the flow must therefore have a very important impact on the surrounding molecular cloud medium. As a considerable amount of energy is being pumped into the clouds in this way, outflows are very important for our understanding of star formation as well as molecular cloud evolution.

The list of molecular outflow sources by Fukui et al. ([1993]) contains 164 sources; only 12 are in the southern hemisphere ( $\delta< -20^{\circ}$ ; excluding the $\rho$ Oph region). Observations of ¹²CO towards IRAS sources have shown that in many cases there is a line wing that indicates the presence of outflows. During our survey in the outer Galaxy (l: 85 $^{\circ}-280^{\circ}$ ) of ¹²CO towards IRAS sources with colours typical of star forming regions (Wouterloot & Brand [1989] [WB89]), we have found about 150 sources (14%) which in their spectra show broad features (wings) that are characteristic of outflow; including also the emission profiles which have a clear blue and/or red asymmetry, we find that 28% (about 300) of the detected sources have distinctly non-Gaussian line profiles. Mapping is required to confirm that broad CO profiles indeed represent outflow sources.

The Vela region ( $245\hbox{$^\circ$ }<l<275$ $^\circ$ ) contains a number of molecular cloud complexes with distances between several 100 pc and several kpc (see e.g. Murphy & May [1991] and Liseau et al. [1992]). In addition there are isolated clouds at larger distances, up to 15 kpc (see Wouterloot et al. [1990]). The WB89 survey in this region contains 208 IRAS sources, 41 of which were noted to have blue and/or red wings in their ¹²CO(1-0) spectrum. From these, we selected eight sources for further study with the aim to derive size, mass, momentum, energy, dynamical timescale, and mechanical luminosity of the outflows in the sample, and to obtain size, temperature, and density of the molecular core from which they originate.

1 Introduction