Large-Scale Flows from Orion South

Multiple optical outflows are known to exist in the vicinity of the activestar formation region called Orion-South (Orion-S). We have mapped the velocityof low ionization features in the brightest part of the Orion Nebula, includingOrion-S, and imaged the entire nebula with the Hubble Space Telescope. Thesenew data, combined with recent high resolution radio maps of outflows from theOrion-S region, allow us to trace the origin of the optical outflows. It isconfirmed that HH 625 arises from the blueshifted lobe of the CO outflow from136-359 in Orion-S while it is likely that HH 507 arises from the blueshiftedlobe of the SiO outflow from the nearby source 135-356. It is likely thatredshifted lobes are deflected within the photon dominated region behind theoptical nebula. This leads to a possible identification of a new large shock tothe southwest from Orion-S as being driven by the redshifted CO outflow arisingfrom 137-408. The distant object HH 400 is seen to have two even furthercomponents and these all are probably linked to either HH 203, HH 204, or HH528. Distant shocks on the west side of the nebula may be related to HH 269.The sources of multiple bright blueshifted Herbig-Haro objects (HH 202, HH 203,HH 204, HH 269, HH 528) remain unidentified, in spite of earlier claimedidentifications. Some of this lack of identification may arise from the factthat deflection in radial velocity can also produce a change in direction inthe plane of the sky. The best way to resolve this open question is throughimproved tangential velocities of low ionization features arising where theoutflows first break out into the ionized nebula.