A High-Resolution Very Large Array Observation of a Protostar in OMC-3: Shock-Induced X-Ray Emission by a Protostellar Jet

摘要

Using the Very Large Array (VLA) in the A-configuration, we obtained a high-resolution 3.6cm map of a hard X-ray source detected by the Chandra X-ray Observatory in a protostellar clump in Orion molecular cloud 3. Two radio continuum sources were detected in the vicinity of the X-ray source, both of which have NIR counterparts. We conclude that these VLA sources are free-free emission produced by shocks in protostellar jets from the NIR class I protostars. Using the centimeter data, we determined the power and orientation of the protostellar jets. The center position of the X-ray emission was found to be ～1"-2" offset from the exciting sources of the jets, and the displacement is in the direction of the jets and molecular outflows. We discuss the nature of the X-ray emission as the shock-excited plasma at the shock front where the jet propagates through the interstellar medium at a speed of ～1000 km s~(-1).