2001AJ....121.3133G

We present high-resolution VLA images taken at the wavelengths of 20, 6, and 3.6 cm in the vicinity of the pulsars PSR B1706-44 (PSR J1709-4428) and PSR B1643-43 (PSR J1646-4346). Both of these pulsars are young (<30,000 yr) and have large spin-down luminosities (Edot>10³⁵ ergs.s^–1) and hence are good candidates to search for extended synchrotron nebulae excited by the relativistic pulsar wind. For PSR B1643-43 we found evidence of a 4' comet-shaped nebula, suggestive of a synchrotron ``wake'' left by a fast-moving pulsar. PSR B1706-44 appears surrounded by a spherical nebula approximately 3' in diameter. Based on their morphology, the detection of significant linear polarization (>20%), and their flat radio spectra (α=0.25-0.3, where S_ν∝ν^–α), we argue that these are wind nebulae powered by the rotational energy loss of the respective pulsars.