A study of the kinematics and temperature of the high-density molecular gas surrounding L1448C

We have performed VLA ammonia (1, 1) and (2, 2) observations of the molecul ar core associated with the very young stellar object L1448C, the powering source of the highly collimated bipolar outflow L1448. The line broadening observed in the molecular core appears to be a consequence of the interacti on between the highly collimated wind from L1448C and the ambient molecular gas. The ammonia line emission shows a velocity gradient in a direction pe rpendicular to the outflow axis, which is consistent with rotation in a cir cumstellar structure. In addition, there is also evidence of a velocity gra dient along the outflow axis, suggesting that the ammonia line emission cou ld be tracing a self-gravitating, thick, disklike structure around L1448C, which appears to be rotating and contracting. We also detect ammonia emissi on associated with IRS 3, the infrared source about 75" northwest of L1448C . This emission presents a wedgelike morphology pointing away from L1448C. We propose that this ammonia structure traces the region where the leading head of the L1448C near-infrared H-2 jet is carving a cavity in the norther n molecular core, or alternatively, where the near-infrared H-2 jet is bein g bent to the west by the northern high-density core. In addition, an antic orrelation between the ammonia and H-2 line emissions is found. The near-in frared H-2 line emission is clearly seen in the relatively low density gap between the northern (IRS 3) and southern (L1448C) molecular cores, while t he high-density molecular gas surrounding L1448C completely obscures this y oung stellar object and its counterjet at optical and near-infrared wavelen gths.