2010A&A...523A..29D

Outflows provide indirect means to gain insight into diverse star formation-associated phenomena. At the level of individual protostellar cores, both outflows and the intrinsic core properties can be used to study the mass accretion/ejection process of heavily embedded protostellar sources. The main objective of the paper is to study the overall outflow distribution and its association with the young population of the Serpens Core cluster. In addition, the paper addresses the correlation of the outflow momentum flux with the bolometric luminosity of their driving sources using this homogeneous dataset for a single star-forming site. An area comprising 460''x230'' of the Serpens cloud core was mapped in ¹²CO J=3->2 with the HARP-B heterodyne array at the James Clerk Maxwell Telescope; J=3->2 observations are more sensitive tracers of hot outflow gas than lower J CO transitions; combined with the high sensitivity of the HARP-B receptors outflows are sharply outlined, enabling their association with individual protostellar cores. Most of ∼20 observed outflows are found to be associated with known protostellar sources in bipolar or unipolar configurations. All but two outflow/core pairs in our sample tend to have a projected orientation spanning roughly NW-SE. The overall momentum driven by outflows in Serpens lies between 3.2 and 5.1x10^–1M_☉km/s, the kinetic energy from 4.3 to 6.7x10⁴³erg, and momentum flux is between 2.8 and 4.4x10^–4M_☉km/s/yr. Bolometric luminosities of protostellar cores based on Spitzer photometry are found up to an order of magnitude lower than previous estimations derived with IRAS/ISO data. We confirm the validity of the existing correlations between the momentum flux and bolometric luminosity of Class I sources for the homogenous sample of Serpens, though we suggest that they should be revised by a shift to lower luminosities. All protostars classified as Class 0 sources stand well above the known Class I correlations, indicating a decline in momentum flux between the two classes.