High Spatial Resolution Observations of NH 3 and CH 3 OH toward the Massive Twin Cores NGC 6334I and NGC 6334I(N)

Abstract

Molecular line observations of NH3 (J, K) - (1, 1) and (2, 2) and CH 3OH at 24.93 GHz taken with the Australian Telescope Compact Array (ATCA) toward the massive twin cores NGC 6334I and NGC 6334I (N) reveal significant variations in the line emission between the two massive cores. The UC H II region/hot core NGC 6334I exhibits strong thermal NH3 and CH3OH emission adjacent to the UC H II region and coincident with two millimeter continuum peaks observed by T. R. Hunter et al. In contrast, we find neither compact NH3 nor thermal CH3OH line emission toward NGC 6334I(N). There the NH3 emission is distributed over a broad region (>1′) without a clear peak, and we find Class I CH 3OH maser emission with peak brightness temperatures up to 7000 K. The maser emission peaks appear to be spatially associated with the interfaces between the molecular outflows and the ambient dense gas. Peak NH3 (1, 1) line brightness temperatures ≥70 K in both regions indicate gas temperatures on the same order. NH3 emission is also detected toward the outflow in NGC 6334I, resulting in an estimated rotational temperature of rrot ∼ 19 K. Furthermore, we observe CH3OH and NH 3 absorption toward the UC H II region; the velocity structure is consistent with expanding molecular gas around the UC H II region. Thermal and kinematic effects possibly imposed from the UC H II region on the molecular core are also discussed. © 2005. The American Astronomical Society. All rights reserved.