Gravitational Infall in the Dense Cores L1527 and L483

Lines of N 2 H + , C 3 H 2 , and H 2 CO show kinematic evidence of gravitational infall in L1527, and probably also in L483. Three trends appear to indicate infall, rather than outflow or rotation: ( a ) at each protostar position, line peak and centroid velocities get bluer by 0.1-0.3 km s -1 with increasing line optical depth; ( b ) in maps of C 3 H 2 and H 2 CO lines, peak and centroid velocities get bluer by a similar amount as positions approach each protostar; and ( c ) C 3 H 2 line widths in L1527 increase as positions approach the protostar. Also, in both sources H 2 CO lines show the infall "signature" of spatially concentrated double-peaked profiles, with their blue peaks brighter than their red peaks, as seen previously in B335. Many asymmetric profiles have a single blueshifted peak with a red shoulder, or two peaks with blue/red intensity ratio greater than 3. These are hard to fit with spherical infall models, owing perhaps to the effects of the bipolar outflow. In each source, H 2 CO line wings show clear evidence of collimated outflow.