A burst of outflows from the Serpens cloud core: wide-field submillimetre continuum, CO J=2-1 and optical observations

Wide-field mapping of Serpens in submillimetre continuum emission and CO J = 2-1 line emission is here complemented by optical imaging in [S II] lambd a lambda 6716, 6731 line emission. Analysis of the 450- and 850-mu m contin uum data shows at least 10 separate sources, along with fainter diffuse bac kground emission and filaments extending to the south and east of the core. These filaments describe 'cavity-like' structures that may have been shape d by the numerous outflows in the region. The dust opacity index, beta, der ived for the identifiable compact sources is of the order of 1.0 +/- 0.2, w ith dust temperatures in excess of 20 K, This value of beta is somewhat low er than for typical class I YSOs; we suggest that the Serpens sources may b e 'warm', late class 0 or early class I objects. With the combined CO and optical data we also examine, on large scales, the outflows driven by the embedded sources in Serpens. In addition to a numbe r of new Herbig-Haro flows (here denoted HH 455-460), a number of high-velo city CO lobes are observed; these extend radially outwards from the cluster of submillimetre sources in the core. A close association between the opti cal and molecular flows is also identified. The data suggest that many of t he submillimetre sources power outflows. Collectively, the outflows traced in CO support the widely recognized correlation between source bolometric l uminosity and outflow power, and imply a dynamical age for the whole protos tellar cluster of similar to 3 x 10(4) yr. Notably, this is roughly equal t o the proposed duration of the 'class 0' stage in protostellar evolution.