, S.Guilloteau , A.Dutrey ,
R.Bachiller 
IRAM, 300 rue de la piscine, F-38406 St Martin d'Hères, France OAN, Apartado 1143, E-28800 Alcalá de Henares, Spain 
( 
), 
( ), and 
2.7 mm continuum emission around
L1157-mm, a suspected protostar powering an energetic molecular outflow.
The continuum emission consists in two distinct components. The Class 0
object L1157-mm is seen as a compact source of size 
(440 AU)
and mass 
, which is marginally resolved and elongated
perpendicular to the outflow axis. In addition, spatially-extended
low-level emission is observed and likely arises at the heated edges
of the cavity excavated by the outflow in the surrounding envelope.
Simple modelisation shows that such an interacting structure can explain
the observed morphology and the spectral energy distribution of the source.
The line observations indicate that mostly originates from the
envelope and the limb-brightened edges of the outflow, whereas the
emission is more directly associated with the compact continuum source.
Weak evidence for rotation has been found. Comparison of the two line
tracers shows proeminent redshifted self-absorption in the spectrum
which is very suggestive of infall motions. The infalling medium seems to
be confined in a large (a few thousands AU) flattened structure.
These observations provide a quite detailed description of the structure of a Class 0 protostar, which appears to have a complex vicinity where the outflowing and accreting phenomena are closely linked together (Fig. 4)
Figure: 2.5'' observations of the protostar
L 1157-mm: (Left) J=1-0 (thick histogram), J=1-0
(filled) and J=1-0
interferometric + single-dish (thin) spectra observed towards the central
position. (Right) 
mm continuum emission (greyscale)
surimposed with the integrated CO emission: the extended component of
the continuum emission is associated with the edges of the molecular
outflow. The white ellipse is the formal result of a fit of the compact
central source.
