Title: The Massive Protostellar Cluster NGC6334I at 220 AU Resolution: Discovery of Further Multiplicity, Diversity and a Hot Multi-Core
Author: C. L. Brogan, T. R. Hunter, C. J. Cyganowski, C. J. Chandler, R. Friesen, R. Indebetouw

We present VLA and ALMA imaging of the deeply-embedded protostellar cluster NGC6334I from 5 cm to 1.3 mm at angular resolutions as fine as 0.17 (220 AU). The dominant hot core MM1 is resolved into seven components at 1.3 mm, clustered within a radius of 1000 AU. Four of the components have brightness temperatures >200 K, radii ~300 AU, minimum luminosities ~10000 Lsun, and must be centrally heated. We term this new phenomenon a "hot multi-core". Two of these objects also exhibit compact free-free emission at longer wavelengths, consistent with a hypercompact HII region (MM1B) and a jet (MM1D). The spatial kinematics of the water maser emission centered on MM1D are consistent with it being the origin of the high-velocity bipolar molecular outflow seen in CO. The close proximity of MM1B and MM1D (440~AU) suggests a proto-binary or a transient bound system. Several components of MM1 exhibit steep millimetre SEDs indicative of either unusual dust spectral properties or time variability. In addition to resolving MM1 and the other hot core (MM2) into multiple components, we detect five new millimetre and two new centimetre sources. Water masers are detected for the first time toward MM4A, confirming its membership in the protocluster. With a 1.3 mm brightness temperature of 97 K coupled with a lack of thermal molecular line emission, MM4A appears to be a highly optically-thick 240 Lsun dust core, possibly tracing a transient stage of massive protostellar evolution. The nature of the strongest water maser source CM2 remains unclear due to its combination of non-thermal radio continuum and lack of dust emission.

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Title: The ionisation toward the high-mass star-forming region NGC 6334 I
Authors: J. L. Morales Ortiz, C. Ceccarelli, D. C. Lis, L. Olmi, R. Plume, P. Schilke

Context. Ionisation plays a central role in the gas-phase chemistry of molecular clouds. Since ions are coupled with the magnetic fields, which can in turn counteract the gravitational collapse, it is of paramount importance to measure their abundance in star-forming regions.
Aims. We use spectral line observations of the high-mass star-forming region NGC 6334 I to derive the abundance of two of the most abundant molecular ions, HCO+ and N2H+, and consequently, the cosmic ray ionisation rate. In addition, the line profiles provide information about the kinematics of this region.
Methods. We present high-resolution spectral line observations conducted with the HIFI instrument on board the Herschel Space Observatory of the rotational transitions with Jup > 5 of the molecular species C17O, C18O, HCO+, H13CO+, and N2H+.
Results. The line profiles display a redshifted asymmetry consistent with a region of expanding gas. We identify two emission components in the spectra, each with a different excitation, associated with the envelope of NGC 6334 I. The physical parameters obtained for the envelope are in agreement with previous models of the radial structure of NGC 6334 I based on submillimetre continuum observations. Based on our new Herschel/HIFI observations, combined with the predictions from a chemical model, we derive a cosmic ray ionisation rate that is an order of magnitude higher than the canonical value of 10^(-17) s-1.
Conclusions. We detect an expansion of the envelope surrounding the hot core of NGC 6334 I, which is mainly driven by thermal pressure from the hot ionised gas in the region. The ionisation rate is dominated by cosmic rays originating from outside the source, although X-ray emission from the NGC 6334 I core could contribute to the ionisation in the inner part of the envelope.

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Title: The distribution of water in the high-mass star-forming region NGC 6334I
Authors: M. Emprechtinger, D. C. Lis, T. Bell, T. G. Phillips, P. Schilke, C. Comito, R. Rolffs, F. van der Tak, C. Ceccarelli, H. Aarts, A. Bacmann, A. Baudry, M. Benedettini, E.A. Bergin, G. Blake, A. Boogert, S. Bottinelli, S. Cabrit, P. Caselli, A. Castets, E. Caux, J. Cernicharo, C. Codella, A. Coutens, N. Crimier, K. Demyk, C. Dominik, P. Encrenaz, E. Falgarone, A. Fuente, M. Gerin, P. Goldsmith, F. Helmich, P. Hennebelle, T. Henning, E. Herbst, P. Hily-Blant, T. Jacq, C. Kahane, M. Kama, A. Klotz, J. Kooi, W. Langer, B. Lefloch, A. Loose, S. Lord, A. Lorenzani, S. Maret, G. Melnick, D. Neufeld, B. Nisini, V. Ossenkopf, S. Pacheco, L. Pagani, B. Parise, J. Pearson, C. Risacher, M. Salez, P. Saraceno, K. Schuster, J. Stutzki, X. Tielens, M. van der Wiel, C. Vastel, S. Viti, V. Wakelam, A. Walters,
F. Wyrowski, H. Yorke,
et al. (2 additional authors not shown)

We present observations of twelve rotational transitions of H2O-16, H2O-18, and H2O-17 toward the massive star-forming region NGC 6334 I, carried out with Herschel/HIFI as part of the guaranteed time key program Chemical HErschel Surveys of Star forming regions (CHESS). We analyse these observations to obtain insights into physical processes in this region.
We identify three main gas components (hot core, cold foreground, and outflow) in NGC 6334 I and derive the physical conditions in these components.
The hot core, identified by the emission in highly excited lines, shows a high excitation temperature of 200 K, whereas water in the foreground component is predominantly in the ortho- and para- ground states. The abundance of water varies between 4 10^-5 (outflow) and 10^-8 (cold foreground gas). This variation is most likely due to the freeze-out of water molecules onto dust grains. The H2O-18/H2O-17 abundance ratio is 3.2, which is consistent with the O-18/O-17 ratio determined from CO isotopologues. The ortho/para ratio in water appears to be relatively low 1.6(1) in the cold, quiescent gas, but close to the equilibrium value of three in the warmer outflow material (2.5(0.8)).

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