Infrared and radio study of the W43 cluster: resolved binaries and
  non-thermal emission
  Context: The recent detection of very high-energy (VHE) gamma-ray emission
from the direction of the W43 star-forming region prompted us to investigate
its stellar population in detail in an attempt to see wether or not it is
possible an association. Aims: We search for the possible counterpart(s) of the
gamma-ray source or any hints of them, such as non-thermal synchrotron emission
as a tracer of relativistic particles often involved in plausible physical
scenarios for VHE emission. Methods: We data-mined several archival databases
with different degrees of success. The most significant results came from radio
and near-infrared archival data. Results: The previously known Wolf-Rayet star
in the W43 central cluster and another cluster member appear to be resolved
into two components,suggesting a likely binary nature. In addition, extended
radio emission with a clearly negative spectral index is detected in
coincidence with the W43 cluster. These findings could have important
implications for possible gamma-ray emitting scenarios, which we also briefly
discuss.
