Authors:
Torrelles J.M., Ho P.T.P., Rodríguez L.F., Cantó J.
Abstract:
We present VLA NH3(1, 1) and NH3(2, 2) observations toward Monoceros R2. The high-density gas shows a remarkable clumpy arclike structure, ∼90″ × 20″, displaced 30″ to the southwest of the edge of the H II region. This arc is apparently part of a 2′ condensation, with its northeastern edge facing the stellar activity center. Within this arc, there is a discernible velocity gradient with the highest velocities away from the stellar activity center. There is also a clear temperature gradient, with the highest temperatures toward the northeastern edge of the arclike structure. These characteristics imply interaction of the exciting source(s) and/or the stellar wind with the ambient dense molecular gas. We propose several scenarios to explain the morphology, kinematics, and excitation of the observed ammonia arclike structure, and possible tests to differentiate between the proposed models.
Keywords:
Interstellar: molecules; Nebulae: H II regions; Nebulae: individual (Mon R2); Nebulae: internal motions