New VLA detections of the variable radio continuum source VLA J181335.1 - 174957 , associated with the energetic X-ray pulsar PSR J1813 - 1749 and the TeV source HESS J1813-178 , are presented .
The radio source has a right circular polarization of \sim 50 \% , and a negative spectral index of -1.3 \pm 0.1 , which show that it is non-thermal .
The radio pulses of the pulsar are not detected from additional Effelsberg observations at 1.4 GHz made within one week of a VLA detection .
This result would appear to support the idea that the continuum radio emission detected with the VLA does not trace the time-averaged emission pulses , as had previously been suggested .
We discuss other possible origins for the radio source , such as a pulsar wind , magnetospheric emission , and a low-mass star companion .
However , observations made at higher frequencies by Camilo et al .
( in preparation ) show that the VLA source is in fact the time-averaged pulsed emission and that the detection of the pulses had not been achieved because this is the most scattered pulsar known .