Discovery of a radio supernova remnant and nonthermal X-rays coincident with the TeV source HESS J1813-178

We present the discovery of nonthermal radio and X-ray emission positionally coincident with the TeV gammaray source HESS J1813 - 178. We demonstrate that the nonthermal radio emission is due to a young shell-type supernova remnant (SNR), G12.8 - 0.0, and constrain its distance to be greater than 4 kpc. The X-ray emission is primarily nonthermal and is consistent with either an SNR shell or unidentified pulsar or pulsar wind nebula origin; pulsed emission is not detected in archival ASCA data. A simple synchrotron plus inverse Compton model for the broadband emission assuming that all of the emission arises from the SNR shell implies maximum energies of (30 - 450)[B/(10 mu G)](-0.5) TeV. Further observations are needed in order to confirm that the broadband emission has a common origin and to better constrain the X-ray spectrum.