Chuang, Chen-Yu (NTU, ASIAA); Aso, Yusuke (ASIAA); Hirano, Naomi (ASIAA)
NGC1333 IRAS4A is a well-studied class 0 protobinary system embedded in a circumbinary envelope. Each protostar of the binary, IRAS4A1 and IRAS4A2, ejects its own outflow toward the north and the south. In order to investigate the outflow envelope system in more detail, we analyzed ALMA archival data of SO (J_N=6_5-5_4) and (J_N=7_6-6_5) line. The high-resolution image (82.3 au * 44.7 au) of SO (J_N=6_5-5_4) successfully separates the two northern outflow lobes connected to IRAS4A1 and IRAS4A2. The SO line emission in IRAS4A2 shows S-shaped morphology, consisting of a flattened structure around IRAS4A2 and the two outflow lobes. The flattened structure has an opposite velocity gradient to that of the circumbinary envelope. The bases of the two outflow lobes appear to be connected to both edges of the flattened structure. Our numerical simulation suggests that those two results, i.e., S-shaped outflow and counter rotation, can be explained by magnetic fields misaligned from the initial rotation axis.