GMRT observations of the protostellar jet associated with \iras
  We report continuum GMRT observations aimed to explore the behavior of the
jet associated with IRAS 16547-4247 at very low frequencies (325 MHz and 610
MHz). The obtained maps reveal an elongated morphology in the SE-NW direction.
In addition, the 610 MHz map shows three knots associated to the elongated
morphology that seems to correspond to the triple radio source identified as
the jet seen at higher frequencies. However, at 325 MHz, although an elongated
morphology is also observed, only two knots appear in the map. By comparing our
knot positions at both frequencies with a precessing jet model used in a
previous work, we find that the knots fall closely to the wiggling path and,
hence, they likely represent shocks of the material of the precessing jet with
the medium. Only the nature of the southernmost knot detected at 325 MHz
remains unclear. Besides, we found that the whole emission of the lobes is
non-thermal down to very low frequencies and that the possible associated
emission mechanisms work differently in in both lobes, causing the
discrepancies between observed frequencies. To explain these discrepancies we
investigate mechanisms such as synchrotron radiative losses in a magnetic field
of about 0.5 mG in the shocks and find this possibility unlikely to occur.
Alternatively, we invoke interaction with an inhomogeneous medium as the most
probable scenario.
