  We have discovered remarkable jet- and arc-like molecular features toward the
rich and young stellar cluster Westerlund2. The jet has a length of ~100 pc and
a width of ~10 pc, while the arc shows a crescent shape with a radius of ~30
pc. These molecular features each have masses of ~10000 solar mass and show
spatial correlations with the surrounding lower density HI gas. The jet also
shows an intriguing positional alignment with the core of the TeV gamma ray
source HESS J1023-575 and with the MeV/GeV gamma-ray source recently reported
by the Fermi collaboration. We argue that the jet and arc are caused by an
energetic event in Westerlund 2, presumably due to an anisotropic supernova
explosion of one of the most massive member stars. While the origin of the TeV
and GeV gamma-ray sources is uncertain, one may speculate that they are related
to the same event via relativistic particle acceleration by strong shock waves
produced at the explosion or by remnant objects such as a pulsar wind nebula or
microquasar.
