ASTROMETRY AND SPATIO-KINEMATICS OF H<sub>2</sub>O MASERS IN THE MASSIVE STAR-FORMING REGION NGC 6334I(NORTH) WITH VERA

Chibueze, James O.; Omodaká, Toshihiro; Handa, Toshihiro; Imai, Hiroshi; Kurayama, Tomoharu; Nagayama, Tomonori; Sunada, Kazuyoshi; Nakano, Makoto; Hirota, Tomoya; Honma, Mareki

doi:10.1088/0004-637x/784/2/114

Cited by 76 publications

(59 citation statements)

References 34 publications

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“…The parameters needed to estimate field strength based on FG 5 FP 1 FT are listed here. All these parameters are derived assuming a distance of 1.7 kiloparsecs to NGC 6334 26 , which has a ,25% uncertainty 48,49 . This uncertainty, however, will not affect the estimate of B, because M (ref.…”

Section: Letter Researchmentioning

confidence: 99%

Self-similar fragmentation regulated by magnetic fields in a region forming massive stars

Yuen

Otto

et al. 2015

Nature

115

134

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Most molecular clouds are filamentary or elongated. For those forming low-mass stars (<8 solar masses), the competition between self-gravity and turbulent pressure along the dynamically dominant intercloud magnetic field (10 to 100 parsecs) shapes the clouds to be elongated either perpendicularly or parallel to the fields. A recent study also suggested that on the scales of 0.1 to 0.01 parsecs, such fields are dynamically important within cloud cores forming massive stars (>8 solar masses). But whether the core field morphologies are inherited from the intercloud medium or governed by cloud turbulence is unknown, as is the effect of magnetic fields on cloud fragmentation at scales of 10 to 0.1 parsecs. Here we report magnetic-field maps inferred from polarimetric observations of NGC 6334, a region forming massive stars, on the 100 to 0.01 parsec scale. NGC 6334 hosts young star-forming sites where fields are not severely affected by stellar feedback, and their directions do not change much over the entire scale range. This means that the fields are dynamically important. The ordered fields lead to a self-similar gas fragmentation: at all scales, there exist elongated gas structures nearly perpendicular to the fields. Many gas elongations have density peaks near the ends, which symmetrically pinch the fields. The field strength is proportional to the 0.4th power of the density, which is an indication of anisotropic gas contractions along the field. We conclude that magnetic fields have a crucial role in the fragmentation of NGC 6334.

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Section: Letter Researchmentioning

confidence: 99%

Self-similar fragmentation regulated by magnetic fields in a region forming massive stars

Yuen

Otto

et al. 2015

Nature

115

134

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“…The distances quoted in red rectangles are parallax distances, in black rectangles are photometric distances, in green rectangles are ambiguity resolved kinematic distances, and the rests are near-kinematic distances. References of parallax distances to several well-known MCCs: G111 (Choi et al 2014), Cygnus X (Rygl et al 2012), W51 (Sato et al 2010), W49 ), G35-W48 (Zhang et al 2009), W43 (Zhang et al 2014), G23.7+60 (Sanna et al 2014), M16/M17 (Xu et al 2011), W33 (Immer et al 2013), W31 (Sanna et al 2014), CMZ ), CMZ ), NGC6334/NGC6357 (Chibueze et al 2014). For ambiguity resolved kinematic distances, we obtain them from Jones & Dickey (2012) and Anderson & Bania (2009).…”

Section: Physical Propertiesmentioning

confidence: 99%

The Scaling Relations and Star Formation Laws of Mini-Starburst Complexes

Nguyen-Luong

Nguyen

Motte

et al. 2016

ApJ

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The scaling relations and the star formation laws for molecular cloud complexes in the Milky Way is investigated using data from the 12 CO 1-0 CfA survey and from the literatures. We compare their masses M gas , mass surface densities Σ Mgas , radii R, velocity dispersions σ, star formation rates SF R, and SFR densities Σ SFR with those of structures ranging from cores, clumps, Giant Molecular Clouds (GMCs), to Molecular Cloud Complexes (MCCs), and to Galaxies, spanning 8 orders of magnitudes in size and 13 orders of magnitudes in mass. MCC are mostly large (R > 50 pc), massive (∼ 10 6 M ⊙ ) gravitationally unbound cloud structures. This results in the following universal relations:Mgas , SF R ∼ M gas 0.9 , and SF R ∼ σ 2.7 .Variations in the slopes and the coefficients of these relations are found at individual scales signifying different physics acting at different scales. Additionally, there are breaks at the MCC scale in the σ − R relation and between the starburst and the normal star-forming objects in the SF R − M gas and Σ SFR -Σ Mgas relations. Therefore, we propose to use the Schmidt-Kennicutt diagram to distinguish the starburst from the normal star-forming structures by applying a Σ Mgas threshold of ∼ 100 M ⊙ pc −2 and a Σ SFR threshold of 1 M ⊙ yr −1 kpc −2 . Mini-starburst complexes are gravitationally unbound MCCs that have enhanced Σ SFR (>1 M ⊙ yr −1 kpc −2 ), probably caused by dynamic events such as radiation pressure, colliding flows, or spiral arm gravitational instability. Because of the dynamical evolution, gravitational boundedness does not play a significant role in characterizing the star formation activity of MCCs, especially the mini-starburst complexes, which leads to the conclusion that the formation of massive stars and clusters is dynamic. We emphasize the importance of understanding mini-starburst in investigating the physics of starburst galaxies.

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“…NGC 6334 is a high-mass star-forming complex that lies in the Carina-Sagittarius arm within the Galactic plane at a relatively nearby distance of 1.3±0.3 kpc (Chibueze et al 2014). NGC 6334 is located in the southern sky as a 100 pc giant filamentary cloud that has been the target of multiple studies at different wavelengths (e.g.…”

Section: Introductionmentioning

confidence: 99%

Physical properties of the star-forming clusters in NGC 6334

Sadaghiani

Sánchez-Monge

Schilke

et al. 2020

A&A

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Aims. We aim to characterise certain physical properties of high-mass star-forming sites in the NGC 6334 molecular cloud, such as the core mass function (CMF), spatial distribution of cores, and mass segregation. Methods. We used the Atacama Large Millimetre/sub-millimetre Array (ALMA) to image the embedded clusters NGC 6334-I and NGC 6334-I(N) in the continuum emission at 87.6 GHz. We achieved a spatial resolution of 1300 au, enough to resolve different compact cores and fragments, and to study the properties of the clusters. Results. We detected 142 compact sources distributed over the whole surveyed area. The ALMA compact sources are clustered in different regions. We used different machine-learning algorithms to identify four main clusters: NGC 6334-I, NGC 6334-I(N), NGC 6334-I(NW), and NGC 6334-E. The typical separations between cluster members range from 4 000 au to 12 000 au. These separations, together with the core masses (0.1-100 M ), are in agreement with the fragmentation being controlled by turbulence at scales of 0.1 pc. We find that the CMFs show an apparent excess of high-mass cores compared to the stellar Initial Mass Function. We evaluated the effects of temperature and unresolved multiplicity on the derived slope of the CMF. Based on this, we conclude that the excess of high-mass cores might be spurious and due to inaccurate temperature determinations and/or resolution limitations. We searched for evidence of mass segregation in the clusters and we find that clusters NGC 6334-I and NGC 6334-I(N) show hints of segregation with the most massive cores located in the centre of the clusters. Conclusions. We searched for correlations between the physical properties of the four embedded clusters and their evolutionary stage (based on the presence of H ii regions and infrared sources). NGC 6334-E appears as the most evolved cluster, already harboring a well-developed H ii region. NGC 6334-I is the second-most evolved cluster with an ultra-compact H ii region. NGC 6334-I(N) contains the largest population of dust cores distributed in two filamentary structures and no dominant H ii region. Finally, NGC 6334-I(NW) is a cluster of mainly low-mass dust cores with no clear signs of massive cores or H ii regions. We find a larger separation between cluster members in the more evolved clusters favoring the role of gas expulsion and stellar ejection with evolution. The mass segregation, seen in the NGC 6334-I and NGC 6334-I(N) clusters, suggests a primordial origin for NGC 6334-I(N). In contrast, the segregation in NGC 6334-I might be due to dynamical effects. Finally, the lack of massive cores in the most evolved cluster suggests that the gas reservoir is already exhausted, while the less evolved clusters still have a large gas reservoir along with the presence of massive cores. In general, the fragmentation process of NGC 6334 at large scales (from filament to clump, i.e. at about 1 pc) is likely governed by turbulent pressure, while at smaller scales (scale of cores and sub-fragments, i.e. a few hundred au) ...

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ASTROMETRY AND SPATIO-KINEMATICS OF H₂O MASERS IN THE MASSIVE STAR-FORMING REGION NGC 6334I(NORTH) WITH VERA

Cited by 76 publications

References 34 publications

Self-similar fragmentation regulated by magnetic fields in a region forming massive stars

Self-similar fragmentation regulated by magnetic fields in a region forming massive stars

The Scaling Relations and Star Formation Laws of Mini-Starburst Complexes

Physical properties of the star-forming clusters in NGC 6334

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ASTROMETRY AND SPATIO-KINEMATICS OF H2O MASERS IN THE MASSIVE STAR-FORMING REGION NGC 6334I(NORTH) WITH VERA

Cited by 76 publications

References 34 publications

Self-similar fragmentation regulated by magnetic fields in a region forming massive stars

Self-similar fragmentation regulated by magnetic fields in a region forming massive stars

The Scaling Relations and Star Formation Laws of Mini-Starburst Complexes

Physical properties of the star-forming clusters in NGC 6334

Contact Info

Product

Resources

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ASTROMETRY AND SPATIO-KINEMATICS OF H₂O MASERS IN THE MASSIVE STAR-FORMING REGION NGC 6334I(NORTH) WITH VERA