Millimeter Multiplicity in NGC 6334 I and I(N)

Hunter, T. R.; Brogan, C. L.; Megeath, S. T.; Menten, K. M.; Beuther, H.; Thorwirth, Sven

doi:10.1086/505965

Cited by 135 publications

(252 citation statements)

References 41 publications

(69 reference statements)

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“…On a spatial scale similar to that of HCH ii and UCH ii regions, continuum emission from dust has been observed by the SMA in the nearby (1.7 kpc) massive star-forming region NGC 6334 by Hunter et al (2006). The dusty clumps of arcsecond scale in NGC 6334 have continuum emission on the order of 1 Jy.…”

Section: Continuum Spectral Indicesmentioning

confidence: 81%

The Early Evolution of Massive Stars: Radio Recombination Line Spectra

Keto

Zhang

Kurtz

2008

ApJ

102

122

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Velocity shifts and differential broadening of radio recombination lines are used to estimate the densities and velocities of the ionized gas in several hypercompact and ultracompact H ii regions. These small H ii regions are thought to be at their earliest evolutionary phase and associated with the youngest massive stars. The observations suggest that these H ii regions are characterized by high densities, supersonic flows, and steep density gradients, consistent with accretion and outflows that would be associated with the formation of massive stars.

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Section: Continuum Spectral Indicesmentioning

confidence: 81%

The Early Evolution of Massive Stars: Radio Recombination Line Spectra

Keto

Zhang

Kurtz

2008

ApJ

102

122

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“…The far-infrared source "I" contains an embedded cluster of NIR sources (Tapia et al 1996). Four compact mm continuum sources are located near the geometric centre of the cluster (Hunter et al 2007). Although NGC 6334I is not known to exhibit strong absorption lines, its OH absorption profiles (Brooks & Whiteoak 2001) reveal two molecular clouds along this line of sight, one with velocities between −15 and 2 km s −1 , and the other near 6 km s −1 .…”

Section: The Sourcesmentioning

confidence: 99%

Detection of interstellar oxidaniumyl: Abundant H₂O⁺towards the star-forming regions DR21, Sgr B2, and NGC6334

Ossenkopf

Müller²,

Lis

et al. 2010

A&A

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Aims. We identify a prominent absorption feature at 1115 GHz, detected in first HIFI spectra towards high-mass star-forming regions, and interpret its astrophysical origin. Methods. The characteristic hyperfine pattern of the H 2 O + ground-state rotational transition, and the lack of other known low-energy transitions in this frequency range, identifies the feature as H 2 O + absorption against the dust continuum background and allows us to derive the velocity profile of the absorbing gas. By comparing this velocity profile with velocity profiles of other tracers in the DR21 star-forming region, we constrain the frequency of the transition and the conditions for its formation.Results. In DR21, the velocity distribution of H 2 O + matches that of the [C ii] line at 158 μm and of OH cm-wave absorption, both stemming from the hot and dense clump surfaces facing the H ii-region and dynamically affected by the blister outflow. Diffuse foreground gas dominates the absorption towards Sgr B2. The integrated intensity of the absorption line allows us to derive lower limits to the H 2 O + column density of 7.2 × 10 12 cm −2 in NGC 6334, 2.3 × 10 13 cm −2 in DR21, and 1.1 × 10 15 cm −2 in Sgr B2.

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“…The SMA resolves the core into several mm peaks (Hunter et al 2006), which show very different emission-line characteristics (Brogan et al 2009). The large-scale environment was mapped by Walsh et al (2010), and an outflow is also present (Beuther et al 2008).…”

Section: Ngc 6334-imentioning

confidence: 99%

Structure of evolved cluster-forming regions

Rolffs

Schilke

Wyrowski

et al. 2011

A&A

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Context. An approach towards understanding the formation of massive stars and star clusters is to study the structure of their hot core phase, an evolutionary stage where dust has been heated, but molecules have not yet been destroyed by ultraviolet radiation. These hot molecular cores are very line-rich, but the interpretation of line surveys is also hampered by poor knowledge of the physical and chemical structure. Aims. To constrain the radial structure of high-mass star-forming regions containing hot cores, we attempt to reproduce by radiative transfer modeling both the intensity and shape of a variety of molecular lines. Methods. We observed 12 hot cores with the Atacama Pathfinder EXperiment (APEX) in lines of HCN, HCO + , CO, and their isotopologues, including high-J lines and vibrationally excited HCN. We investigate how well the sources can be modeled as centrally heated spheres with a power-law density gradient, making use of the radiative transfer code RATRAN and the radial profile of the submm continuum emission, taken from the APEX Telescope Large Area Survey of the GALaxy (ATLASGAL). Results. Most of the observed lines have complicated shapes that incorporate self-absorption, asymmetries, and line wings. Vibrationally excited HCN is detected in all sources, and vibrationally excited H 13 CN in half of the sources. We are able to successfully model most features seen in the APEX data, such as the ratio of the isotopologue lines (very high optical depths), self-absorption (temperature gradient), blue asymmetries (moderate infall), vibrationally excited HCN (high inner temperatures), and H 13 CN (high HCN abundance under dense and hot conditions). Other features could not be reproduced, such as an occasional lack of self-absorption, the emission from high-J lines in the outer pixels of the CHAMP+ receiver (15 −20 from the center), the outflow wings, and the red asymmetric profiles. Conclusions. The amount of molecular gas, in particular of HCN, at very high temperatures is larger than previously thought. A complex interplay between infall and outflow motions is present. Our basic model assumptions of pure central heating and a power-law radial density distribution can serve as approximations for most sources, but are too simple to explain all observed lines. In particular, taking into account clumpiness, multiplicity of heating sources and a more complex velocity field seems to be necessary to more closely match model calculations to observations. This would require three-dimensional radiative transfer modeling of high-resolution interferometric data.

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Millimeter Multiplicity in NGC 6334 I and I(N)

Cited by 135 publications

References 41 publications

The Early Evolution of Massive Stars: Radio Recombination Line Spectra

The Early Evolution of Massive Stars: Radio Recombination Line Spectra

Detection of interstellar oxidaniumyl: Abundant H₂O⁺towards the star-forming regions DR21, Sgr B2, and NGC6334

Structure of evolved cluster-forming regions

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Millimeter Multiplicity in NGC 6334 I and I(N)

Cited by 135 publications

References 41 publications

The Early Evolution of Massive Stars: Radio Recombination Line Spectra

The Early Evolution of Massive Stars: Radio Recombination Line Spectra

Detection of interstellar oxidaniumyl: Abundant H2O+towards the star-forming regions DR21, Sgr B2, and NGC6334

Structure of evolved cluster-forming regions

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Detection of interstellar oxidaniumyl: Abundant H₂O⁺towards the star-forming regions DR21, Sgr B2, and NGC6334