Mid-IR observations of small stellar clusters surrounding Herbig AeBe stars

We present morphological and spectroscopic studies of the northwest rim of the supernova remnant RX J1713.7-3946 based on observations by the Chandra X-ray observatory. We found a complex network of nonthermal (synchrotron) X-ray filaments, as well as a "void" type structure - a dim region of a circular shape - in the northwest rim. It is remarkable that despite distinct brightness variations, the X-ray spectra everywhere in this region can be well fitted with a power-law model with photon index ranging (gamma) = 2.1-2.5. We briefly discuss some implications of these results and argue that the resolved X-ray features in the northwest rim may challenge the perceptions of the standard diffusive shock-acceleration models concerning the production, propagation and radiation of relativistic particles in supernova remnants.