2009ApJ...697.1457F

We present combined interferometer and single dish telescope data of NH₃(J, K) = (1,1) and (2,2) emission toward the clustered star forming Ophiuchus B, C, and F Cores at high spatial resolution (∼1200 AU) using the Australia Telescope Compact Array, the Very Large Array, and the Green Bank Telescope. While the large-scale features of the NH₃(1,1) integrated intensity appear similar to 850 µm continuum emission maps of the Cores, on 15'' (1800 AU) scales we find significant discrepancies between the dense gas tracers in Oph B, but good correspondence in Oph C and F. Using the CLUMPFIND structure identifying algorithm, we identify 15 NH₃ clumps in Oph B, and three each in Oph C and F. Only five of the Oph B NH₃ clumps are coincident within 30'' (3600 AU) of a submillimeter clump. We find v_LSR varies little across any of the cores, and additionally varies by only ∼1.5 km/s between them. The observed NH₃ line widths within the Oph B and F Cores are generally large and often mildly supersonic, while Oph C is characterized by narrow line widths which decrease to nearly thermal values. We find several regions of localized narrow line emission (Δv ≲ 0.4 km/s), some of which are associated with NH₃clumps. We derive the kinetic temperatures of the gas, and find they are remarkably constant across Oph B and F, with a warmer mean value (T_K= 15 K) than typically found in isolated regions and consistent with previous results in clustered regions. Oph C, however, has a mean T_K = 12 K, decreasing to a minimum T_K= 9.4 K toward the submillimeter continuum peak, similar to previous studies of isolated starless clumps. There is no significant difference in temperature toward protostars embedded in the Cores. NH₃ column densities, N(NH₃), and abundances, X(NH₃), are similar to previous work in other nearby molecular clouds. We find evidence for a decrease in X(NH₃) with increasing N(H₂) in Oph B2 and C, suggesting the NH₃ emission may not be tracing well the densest core gas.