We present submillimeter-and millimeter-wave maps tracing the molecular gas and dust around the edge of the H ii region M8. The molecular material is clumped into cores on the scale of the beam (about 0.1 pc) whose temperatures can be estimated from CO observations. The masses of the clumps, estimated from their continuum fluxes, are consistent with a power-law mass function with index À1:7 AE 0:6, which agrees with determinations for other molecular clouds at similar resolutions, using molecular lines as tracers. The submillimeter clumps are sited at the interface between the H ii region and the background molecular cloud, where they are exposed to the ultraviolet flux of OB stars. The physical parameters of the clumps are compared to published models of molecular clouds undergoing photoevaporation, suggesting that the pressure of the ionized gas exceeds the internal pressure of the clumps and, therefore, that a shock front will be driven into the clumps. The clumps themselves currently appear to be gravitationally unbound, but the compression may be sufficient to induce collapse.

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A B S T R A C TThe northern section of the molecular cloud complex NGC 6334 has been mapped in the CO and CS spectral line emission and in continuum emission at a wavelength of 1300 mm. Our observations highlight the two dominant sources, I and I(N), and a host of weaker sources. NGC 6334 I is associated with a cometary ultracompact H ii region and a hot, compact core #10 arcsec in size. Mid-infrared and CH 3 OH observations indicate that it is also associated with at least two protostellar sources, each of which may drive a molecular outflow. For region I we confirm the extreme high-velocity outflow first discovered by Bachiller & Cernicharo and find that it is very energetic with a mechanical luminosity of 390 L ( . A dynamical age for the outflow is ,3000 yr. We also find a weaker outflow originating from the vicinity of NGC 6334 I. In CO and CS this outflow is quite prominent to the north-west, but much less so on the eastern side of I, where there is very little molecular gas. Spectral survey data show a molecular environment at position I which is rich in methanol, methyl formate and dimethyl ether, with lines ranging in energy up to 900 K above the ground state. NGC 6334 I(N) is more dense than I, but cooler, and has none of the high-excitation lines observed toward I. I(N) also has an associated outflow, but it is less energetic than the outflow from I. The fully sampled continuum map shows a network of filaments, voids and cores, many of which are likely to be sites of star formation. A striking feature is a narrow, linear ridge which defines the western boundary. It is unclear if there is a connection between this filament and the many potential sites of star formation, or if the filament existed prior to the star formation activity.

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