The radio afterglow and the host galaxy of the X-ray-rich GRB 981226

We report the discovery of a radio transient VLA 232937.2-235553, coinciden t with the proposed X-ray afterglow for the gamma-ray burst GRB 981226. Thi s gamma-ray burst (GRB) has the highest ratio of X-ray to gamma-ray fluence of all the GRBs detected by BeppoSAX so far, and yet no corresponding opti cal transient was detected, The radio light curve of VLA 232937.2-235553 is qualitatively similar to that of several other radio afterglows. At the su barcsecond position provided by the radio detection, optical imaging reveal s an extended R = 24.9 mag object, which we identify as the host galaxy of GRB 981226, Afterglow models that invoke a jetlike geometry for the outflow or that require an ambient medium with a radial density dependence, such a s that produced by a wind from a massive star, are both consistent with the radio data. Furthermore, we show that the observed properties of the radio afterglow can explain the absence of an optical transient without the need for large extinction local to the GRB.